A car bomb exploded in a crowd of worshippers leaving a mosque after Friday prayers in a mountain rebel stronghold in northern Yemen, killing at least eight people and wounding about 45, government officials said.

Most of the victims were filing out of the Bin Salman mosque in central Saada when explosives hidden in a parked car went off next to the building, a local official said. A security official said at least eight people were killed and about 45 wounded.

Both men spoke on condition of anonymity because they were not authorized to talk to media.

Ambulances rushed to the mosque and unloaded paramedics who scrambled to carry victims' bodies to nearby hospitals. Worshipper Mohammed Abdel Bari said he was inside the mosque when he heard a strong explosion.

"I saw crowds of people and two charred vehicles — I think one of them was the car bomb," Abdel Bari said. "I saw scores of people laying on the ground."

Saada is nestled in a remote, mountainous area on the Saudi Arabian border, about 200 kilometers (124 miles) north of Yemen's capital, San'a.

Thousands of people have been killed in the area since a Shiite Muslim rebellion erupted there in June 2004. The rebels accuse the Yemeni government of corruption and say it is too closely allied with the West, while the government accuses rebel leader Abdel-Malek al-Hawthi of sedition, forming an illegal armed group and inciting anti-American sentiment.

Yemen is a key U.S. ally in the Middle East but also the ancestral homeland of Osama bin Laden. The northern rebels are Shiite Muslims and not allied with bin Laden's Sunni Al Qaeda network, which also has an active presence in the country.

The Shiite fighters signed two cease-fire agreements with the government in June 2007 and in January of this year, but sporadic violence continues.

It was not immediately clear who was behind the attack, the security official said.

But it came a day after Yemen's military announced the deaths of seven army troops, which it blamed on the Saada rebels. Top Yemeni defense officials and army generals arrived in Saada late Thursday, and more government troops were expected to be deployed to the area even before news of Friday's attack, he said.

Saada residents fear a new round of bloody warfare between government forces and al-Hawthi. His followers have so far refused to hand over their weapons and accuse the government of not fulfilling its obligations under the cease-fire agreements, which include freeing rebel detainees, paying compensation to victims and rebuilding villages ravaged by fighting.

Yemen's Shiite rebellion erupted nearly four years ago when al-Hawthi's brother, cleric Hussein Badr Eddin, ordered his followers to take up arms against the government. The cleric was eventually killed in a battle later that year, but his brother has since assumed his role as rebel leader.

Saada's mountain villages turned into a war zone after clashes renewed in late January between rebel fighters and thousands of government troops backed by tanks, artillery and helicopters. Tribal leaders in the northern region say more than 30,000 residents have been displaced by the fighting.