Clashes between rebels and Yemeni troops have resumed in the wake of a devastating bomb attack outside mosque that killed 18 worshippers, a government official said Saturday. Three soldiers and four rebels died in the overnight skirmishes which took place in the remote mountain province of Saada, near the Saudi border, where a rebellion by a small Shi'ite Muslim sect has been raging for the last four years. The official, who spoke on condition of anonymity because he was not authorized to talk to the press, added that a committee of government officials was looking to restart mediation efforts with the rebels of the Shi'ite Muslim al-Zaydi sect. Meanwhile, families on Saturday buried their dead from the blast which also wounded dozens. The bomb rigged to motorcycle blew up amid a crowd of worshippers leaving Friday prayers at a mosque in a rebel stronghold of northern Yemen. The government of predominantly Sunni Yemen blamed the bombing of the Shi'ite mosque on rebel leader Abdel-Malek al-Hawthi and said six people had been arrested in Saada. But al-Hawthi denied involvement and accused senior army officers of staging the bombing to stoke tensions between the rebels and government. The Shi'ite rebels accuse the government of corruption and of being too closely allied with the West. The government accuses al-Hawthi of sedition, forming an illegal armed group and inciting anti-American sentiment. Yemen is a key US ally in the Middle East but is also the ancestral homeland of Osama bin Laden and al-Qaida is active in the country. Recently there have been a series of attacks in Yemen targeting foreigners. But car bombings and attacks on mosques are both rare in Yemen and analysts said the targeting of a mosque is a dangerous escalation in the northern conflict. The 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 and his brother has since assumed the role of rebel leader. The Shi'ite fighters signed two cease-fire agreements with the government in June 2007 and January of this year, but sporadic violence continues. Saada residents now fear a new round of bloody fighting between the government and rebels. Al-Hawthi's followers have so far refused to hand over their weapons. They 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. The mosque attack came a day after Yemen's military announced the deaths of seven troops and blamed 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 Friday's attack.