Nigerian police say a suicide car bomber has killed at least six soldiers and one civilian in an attack in the northeastern state of Yobe.

Yobe state police commissioner Patrick Egbuniwe said the bomber detonated his vehicle Sunday, as security forces were chasing him in the city of Damaturu.

There was no immediate claim of responsibility. Nigerian authorities have blamed the Islamic militant group Boko Haram for many deadly bombings and shootings in the country in recent years.

Boko Haram says it is fighting to create an Islamic state in northern Nigeria and does not recognize the Nigerian government or the constitution.

Nigeria has a history of sectarian violence, especially in the country's Middle Belt, where the mainly Muslim north meets the predominantly Christian south.

U.S. President Barack Obama has offered formal condolences and continued U.S. support to Bulgaria, as investigators probe the suicide bombing that killed five Israeli tourists and a bus driver Wednesday in the Black Sea port city of Burgas.

The official phone call to Prime Minister Boyko Borisov, described in a White House statement Friday, came as Bulgarian police, the FBI and Interpol scoured the blast site and pressed to identify the bomber. Interior Minister Tsvetan Tsvetanov told reporters Friday the bomber was a foreigner who had been in the country for at least four days.

In Israel, where the five tourists were buried Friday, authorities continued to accuse the Iranian-backed militant group Hezbollah in the bombing. Iran has denied involvement.

Authorities described the suspect, caught earlier on surveillance video, as a male about 36 years old who was carrying a bulky backpack shortly before the blast, as well as a fake driver's license

Israeli officials say the Bulgaria bombing was part of a series of recent attacks targeting Israelis in Thailand, India, Georgia, Kenya and Cyprus.

China says three people have been killed and four others seriously wounded in an apparent suicide bombing, when a woman protesting the government-ordered demolition of her house detonated explosives at a local housing office in southwestern China.

The official Xinhua news agency quotes a local report saying the woman, who died instantly, was attempting to negotiate compensation for the loss of her home in Zhaotong, a city in Yunnan province.

The report quotes a witness as saying the suspected bomber detonated the explosives after officials asked her to sign housing documents.

No other details were immediately reported. But forced relocations by local governments attempting to boost land development have in recent years sparked several high-profile protests, including the 2011 takeover of a village in southern China by irate residents protesting unfair land seizures.

Two former officials in Wukan village were expelled from the Communist party for their alleged roles in those seizures, which turned violent after a protest leader died in police custody.

Separately, two civilians died in a 2011 suicide attack by a jobless man in the eastern city of Fuzhou who complained of losing two homes in recent years to government-ordered demolitions.

Three people in 2010 set themselves on fire in Fuzhou in a separate dispute about a government-ordered house demolition. One died.

Somali militant group al-Shabab has claimed responsibility for a suicide car bomb explosion Wednesday outside a hotel in the capital, Mogadishu.

At least 15 people were killed in the attack and dozens more wounded, including Somali parliament members.

The Hotel Muna, which is next to the Somali presidential palace, is known as a residence and gathering point for Somali lawmakers.

Lawmaker Liban Abdullahi Diriye told VOA a small car full of explosives was detonated at a cafe next to the hotel.

An al-Shabab suicide bomber attacked the same hotel in August of 2010. At least 32 people died in that attack, including six lawmakers.

Somali government forces and African Union troops recently drove al-Shabab out of its last Mogadishu strongholds, but the group has continued to bomb and attack targets in the city.

A suspected suicide car bomber has attacked a hotel in Somalia's capital, Mogadishu, killing at least nine people and wounding many more.

The bomber attacked the Hotel Muna, which is next to the Somali presidential palace, and is known as a residence and gathering point for Somali lawmakers.

Officials say the bomber set off a car full of explosives Wednesday at a cafe outside the hotel where many people were sitting.

There was no immediate claim of responsibility for the attack.

Militants attacked the same hotel in August of 2010.

Afghan officials say a car bombing outside a Kandahar police headquarters killed five police officers and two civilians Sunday.

Officials say 19 others were wounded, including 10 civilians, in the bomb attack in southern Afghanistan.

So far, no one has claimed responsibility for the deadly blast.

The explosion comes a day after a top U.S. military commander in Afghanistan called on the Taliban to stop the killing of innocent men, women and children.

General John Allen was responding to a new United Nations report that said 3,021 civilians were killed in Afghanistan in 2011.

The U.N. report said 2011 was the fifth year in a row that civilian casualties increased, jumping 8 percent from 2010.

The reports said insurgents were responsible for more than 2,300 deaths, compared to just 410 civilian deaths by NATO or Afghan government forces.

Afghan officials say a car bombing outside a Kandahar police headquarters killed five police officers and two civilians Sunday.

Officials say 19 others were wounded, including 10 civilians, in the bomb attack in southern Afghanistan.

So far, no one has claimed responsibility for the deadly blast.

The explosion comes a day after a top U.S. military commander in Afghanistan called on the Taliban to stop the killing of innocent men, women and children.

General John Allen was responding to a new United Nations report that said 3,021 civilians were killed in Afghanistan in 2011.

The U.N. report said 2011 was the fifth year in a row that civilian casualties increased, jumping 8 percent from 2010.

The reports said insurgents were responsible for more than 2,300 deaths, compared to just 410 civilian deaths by NATO or Afghan government forces.

The death toll from suicide attacks rose dramatically in 2011 to 450 , an increase of 80 percent over 2010.

On the streets of Kabul, some residents rejected the report’s findings, blaming the majority of the deaths on NATO bombing missions. Others said the number of casualties seemed too low with the increasing number of suicide attacks in areas the U.N. is unable to monitor.

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Diplomats with the United Nations nuclear agency say they will hold talks in Tehranlater this month on allegations that Iran is secretly building a nuclear weapon.

Iran has always denied the charge, insisting its nuclear program is strictly peaceful. It has refused to directly talk about the issue with Western negotiators.

The European Union is planning an Iranian oil embargo. Iran says it would respond by shutting down vital Persian Gulf oil shipping lanes — something the United States says it will not let happen.

Iran is seething with anger over Wednesday's assassination of a top-ranking nuclear scientist in Tehran. Iran blames the United States and Israel and is demanding the U.N. Security Council condemn the murder. An editorial in Iran's Kayhan newspaper called for assassinations of Israeli military and other officials.

Israel and the United States deny involvement. But U.S. Defense Secretary Leon Panetta said Thursday U.S. officials have some ideas who may be responsible.

Iranian media say two men on a motorcycle attached a bomb to a car, killing nuclear scientist Mostafa Ahmadi Roshan. Roshan was a supervisor at the Natanz nuclear facility, Iran's main uranium enrichment site.

Attackers have killed or wounded several Iranian nuclear scientists in recent years, including blasts in late 2010 that state media also attributed to bombs placed on cars by motorcyclists.

The killing of an Iranian nuclear scientist this week has provoked a wave of anger in Tehran, which blames Israel and the United States for the attack.

A hardline Iranian newspaper called on Thursday for retaliation against Israel, which Iranian authorities say orchestrated Wednesday's bomb blast. An editorial in the Kayhan newspaper called for assassinations of Israeli military and other officials.

The comments follow Tehran's call for the United Nations to condemn the attack and take steps toward eliminating what it called terrorism.

Both Israel and the United States have denied any role in the killing of the Iranian nuclear scientist.

The United States, other Western countries and Israel suspect Iran is using its nuclear program to build weapons. Iran says its nuclear ambitions are peaceful, and that the attack will not delay work on the program.

The scientist killed in the attack — Mostafa Ahmadi Roshan — supervised a department at the Natanz nuclear facility, Iran's main uranium enrichment site.

Iranian officials confirmed that a new underground complex has started refining uranium, and diplomats with ties to the U.N. nuclear agency say the work is being done at a much higher lever of purity.

Attackers have killed or wounded several Iranian nuclear scientists in recent years, including blasts in late 2010 that state media also attributed to bombs placed on cars by motorcyclists.

Iranian media said Wednesday two unidentified people on a motorcycle attached a magnetic bomb to Roshan's car. His driver was also killed.