A suicide attack on Wednesday rocked a local market in Yemen's northern city of Saada killing two civilians, a Zaidi Ansar Allah rebel told AFP.
The attacker detonated a bomb-laden motorbike in the middle of the market, said the rebel, who spoke on condition of anonymity.
The blast left another 11 people critically wounded, he added.
The rebels belonging to the Zaidi sect – an offshoot of Shia Islam – have controlled the northern part of Yemen since a 2004 uprising they launched against the central government in Sanaa, complaining of marginalization.
Tensions have been running high between the Zaidis and the government as well as with Sunni extremists, such as Al-Qaeda in the Arabian Peninsula, which has presence in the country's south.
On Monday, authorities in Sanaa announced they had dismantled a bomb planted in a car parked outside a Zaidi religious center headed by a rebel leader in the Yemeni capital Sanaa.
The rebels staged several protests in Sanaa this month after 13 Ansar Allah members were killed and dozens wounded in a gunfight that erupted when rebels, among a crowd demanding the release of members of their community, attacked the national security headquarters with automatic weapons and grenades.
Representatives of Ansar Allah (Supporters of God), are taking part in a national dialogue conference, launched in February to draft a new constitution and prepare for elections in February 2014.
Fighting between the Zaidis and Yemeni forces following the 2004 rebellion killed thousands of people before a ceasefire was reached in February 2010.