At least 30 people were killed in overnight sectarian clashes between Shi'ite rebels and Sunni fundamentalists in Yemen's northern restive province of Saada, officials said on Monday.

"The initial tally showed that at least 25 Shi'ite rebels and five Sunni fundamentalist were killed in fierce fighting in the district of Kutaf in Saada," a government official told Xinhua on condition of anonymity.

Dozens of others were wounded in the three-day clashes as the Shi'ite rebels were trying to recapture areas run by the Sunni tribal fighters, he said.

According to the Defense Ministry, Saada governor Hassan Manna' a has been trying to mediate a ceasefire between the rival forces.

The Shi'ite rebels, also known as al-Houthis, control the most parts of Saada after a six-year sporadic war against the Yemeni government troops. The two sides reached a ceasefire deal in August 2010.

The al-Houthis agreed last week to join a national reconciliation dialogue at the invitation of President Abd-Rabbu Mansour Hadi to pave the way for constitutional reforms and presidential elections two years later.

However, the Shi'ite rebels have since involved in sectarian clashes with local Sunni tribesmen, which rocked the northern regions and forced thousands of local residents to flee to remote areas.

The tension has escalated after the central government's control is weakened by one-year protests against former President Ali Abdullah Saleh, as the well-armed rebel group has been trying to take advantage of the security vacuum to expand their control over the country's northern regions.

Hadi, who replaced Saleh in February in line with a UN-backed power transfer deal, has promised to launch a national dialogue to settle disputes between all political factions.