Nigeria bombing kills 20

[CNN]

Lagos, Nigeria (CNN)A bomb killed 20 people in north-central Nigeria on Tuesday, a state governor said -- marking just the latest in a series of recent deadly attacks in a country where the government is battling the Islamic extremist group Boko Haram.Tuesday's blast, which a witness told CNN happened at a local government building, occurred in the Sabon Gari section of the city of Zaria in Kaduna state, Kaduna Gov. Nasir El-Rufai said on Twitter.

"We call on our citizens to be vigilant and avoid crowded places like markets, mosques, churches and motor parks in the next few weeks," El-Rufai said in one of his tweets following the incident.

I am sad that a terrorist bomb attack just killed 20 people in Sabon Gari Zaria. May the souls of our innocent departed rest in peace, Amen.

— Nasir Ahmad El-Rufai (@elrufai) July 7, 2015

Also Tuesday: In Kenya, at least 14 killed in attack on residential building

Northern Nigeria has seen near-daily attacks on civilian and government targets since last week, leaving more than 200 dead. Witnesses and government officials have blamed last week's attacks on Boko Haram, the terror group that has been fighting the Nigerian government for more than a decade, pushing to bring an extreme version of Islamic law, or Sharia, to the masses.No group immediately claimed responsibility for Tuesday's attack in Zaria.

A summary of northern Nigeria's bloody July:

• On July 1, Boko Haram fighters raided villages in northeastern Nigeria's Borno state, killing more than 150 people, witnesses and government officials said.

• On Sunday in Jos state, just east of Kaduna, an explosion ripped through a restaurant full of customers in a shopping complex. Also in Jos that day, attackers shot at a crowded mosque before launching a rocket-propelled grenade at the building. At least 44 people were killed and 47 others were injured in the pair of attacks, said Mohammed Abdussalam, an official at Nigeria's National Emergency Management Agency. No claims of responsibility were immediately made.Boko Haram: Nigeria's crisis  22 photosBoko Haram: Nigeria's crisis  22 photosA video of Abubakar Shekau, who claims to be the leader of the Nigerian Islamist extremist group Boko Haram, is shown in September 2013. Boko Haram is an Islamist militant group waging a campaign of violence in northern Nigeria. The group's ambitions range from the stricter enforcement of Sharia law to the total destruction of the Nigerian state and its government. Click through to see recent bloody incidents in this strife-torn West African nation:Hide Caption 1 of 22Boko Haram: Nigeria's crisis  22 photosHide Caption 2 of 22Boko Haram: Nigeria's crisis  22 photosBodies lie in the streets in Maiduguri, Nigeria, after religious clashes on July 31, 2009. Boko Haram exploded onto the national scene in 2009 when 700 people were killed in widespread clashes across the north between the group and the Nigerian military. Hide Caption 3 of 22Boko Haram: Nigeria's crisis  22 photosAn official displays burned equipment inside a prison in Bauchi, Nigeria, on September 9, 2010, after the prison was attacked by suspected members of Boko Haram two days earlier. About 720 inmates escaped during the prison break, and police suspect the prison was attacked because it was holding 80 members of the sect.Hide Caption 4 of 22Boko Haram: Nigeria's crisis  22 photosNigerian President Goodluck Jonathan, second from left, stands on the back of a vehicle after being sworn-in as President during a ceremony in the capital of Abuja on May 29, 2011. In December 2011, Jonathan declared a state of emergency in parts of the country afflicted by violence from Boko Haram.Hide Caption 5 of 22Boko Haram: Nigeria's crisis  22 photosRescue workers help a wounded person from a U.N. building in Abuja, Nigeria, on August 26, 2011. The building was rocked by a bomb that killed at least 23 people, leaving others trapped and causing heavy damage. Boko Haram had claimed responsibility for the attack in which a Honda packed with explosives rammed into the U.N. building, shattering windows and setting the place afire. Hide Caption 6 of 22Boko Haram: Nigeria's crisis  22 photosA photo taken on November 6, 2011, shows state police headquarters burned by a series of attacks that targeted police stations, mosques and churches in Damaturu, Nigeria, on November 4, 2011. Attackers left scores injured -- probably more than 100 -- in a three-hour rampage, and 63 people died.Hide Caption 7 of 22Boko Haram: Nigeria's crisis  22 photosMen look at the wreckage of a car after a bomb blast at St. Theresa Catholic Church outside Abuja on December 25, 2011. A string of bombs struck churches in five Nigerian cities, leaving dozens dead and wounded on the Christmas holiday, authorities and witnesses said. Boko Haram's targets included police outposts and churches as well as places associated with "Western influence."Hide Caption 8 of 22Boko Haram: Nigeria's crisis  22 photosA paramedic helps a young man as he leaves a hospital in the northern Nigerian city of Kano on January 21, 2012. A spate of bombings and shootings left more than 200 people dead in Nigeria's second-largest city. Three days later, a joint military task force in Nigeria arrested 158 suspected members of Boko Haram.Hide Caption 9 of 22Boko Haram: Nigeria's crisis  22 photosA photo taken on June 18, 2012, shows a car vandalized after three church bombings and retaliatory attacks in northern Nigeria killed at least 50 people and injured more than 130 others, the Nigerian Red Cross Society said. Hide Caption 10 of 22Boko Haram: Nigeria's crisis  22 photosA French family kidnapped February 19, 2013, in northern Cameroon is released after two months in captivity in Nigeria. The family of four children, their parents and an uncle were kidnapped in Waza National Park in northern Cameroon, situated near the border with Nigeria. One of the captive men read a statement demanding that Nigeria and Cameroon free jailed members of Boko Haram.Hide Caption 11 of 22Boko Haram: Nigeria's crisis  22 photosA soldier stands in front of a damaged wall and the body of a prison officer killed during an attack on a prison in the northeastern Nigerian town of Bama on May 7, 2013. Two soldiers were killed during coordinated attacks on multiple targets. Nigeria's military said more than 100 Boko Haram militants carried out the attack. Hide Caption 12 of 22Boko Haram: Nigeria's crisis  22 photosA deserted student hostel is shown on August 6, 2013, after gunmen stormed a school in Yobe state, killing 20 students and a teacher, state media reported.Hide Caption 13 of 22Boko Haram: Nigeria's crisis  22 photosA photograph made available by the Nigerian army on August 13, 2013, shows improvised explosive devices, bomb-making materials and detonators seized from a Boko Haram hideout. Gunmen attacked a mosque in Nigeria with automatic weapons on August 11, 2013, killing at least 44 people.Hide Caption 14 of 22Boko Haram: Nigeria's crisis  22 photosNigerian students from Jos Polytechnic walk on campus in Jos, Nigeria, on September 30, 2013. Under the cover of darkness, gunmen approached a college dormitory in a rural Nigerian town and opened fire on students who were sleeping. At least 40 students died, according to the News Agency of Nigeria.Hide Caption 15 of 22Boko Haram: Nigeria's crisis  22 photosSoldiers stand outside the 79 Composite Group Air Force base that was attacked earlier in Maiduguri on December 2, 2013. Hundreds of Boko Haram militants attacked an Air Force base and a military checkpoint, according to government officials.Hide Caption 16 of 22Boko Haram: Nigeria's crisis  22 photosCatholic priest Georges Vandenbeusch speaks to reporters outside Paris after his release on January 1, 2014. Vandenbeusch was snatched from his parish church in Cameroon on November 13. Boko Haram claimed responsibility for kidnapping the priest.Hide Caption 17 of 22Boko Haram: Nigeria's crisis  22 photosA man receives treatment at Konduga specialist hospital after a gruesome attack on January 26, 2014. It was suspected that Boko Haram militants opened fire on a village market and torched homes in the village of Kawuri, killing at least 45 people.Hide Caption 18 of 22Boko Haram: Nigeria's crisis  22 photosPolice officers stand guard in front of the burned remains of homes and businesses in the village of Konduga on February 12, 2014. Suspected Boko Haram militants torched houses in the village, killing at least 23 people, according to the governor of Borno state on February 11.Hide Caption 19 of 22Boko Haram: Nigeria's crisis  22 photosYobe state Gov. Ibrahim Gaidam, left, looks at the bodies of students inside an ambulance outside a mosque in Damaturu. At least 29 students died in an attack on a federal college in Buni Yadi, near the capital of Yobe state, Nigeria's military said on February 26, 2014. Authorities suspect Boko Haram carried out the assault in which several buildings were also torched.Hide Caption 20 of 22Boko Haram: Nigeria's crisis  22 photosRescue workers try to put out a fire after a bomb exploded at the busiest roundabout near the crowded Monday Market in Maiduguri on July 1, 2014.Hide Caption 21 of 22Boko Haram: Nigeria's crisis  22 photosPolice in riot gear block a route in Abuja on October 14, 2014, during a demonstration calling on the Nigerian government to rescue schoolgirls kidnapped by Boko Haram. In April, more than 200 girls were abducted from their boarding school in northeastern Nigeria, officials and witnesses said.Hide Caption 22 of 22EXPAND GALLERY• On Sunday in the city of Potiskum in Yobe state, a suicide bomber blew himself up in a church, killing the priest and four other worshippers, witnesses and police said.

• On Monday in the city of Kano, explosives carried by a 13-year-old female suicide bomber detonated near a mosque. The girl died; no one else was hurt, police said.

Nigerian President Muhammadu Buhari on Friday called last week's attacks "inhuman and barbaric" and pledged that every last "Boko Haram bandit ... would be hunted down without mercy and compromise."

Elected earlier this year, Buhari vowed to focus on the fight against the terrorist group, which has pledged allegiance to ISIS. But so far, he has struggled to stop the heavy bloodshed in the Northeast.

Along with suicide bombings, Boko Haram has attacked churches and mosques, raided once-peaceful villages and kidnapped people young and old, most infamously more than 200 girls taken in April 2014 from a school in Chibok.

Boko Haram's strongest presence is in northern Nigeria, where the majority of the country's Muslims live. The country's south is largely Christian and animist.

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Source: CNN