A suicide bomb attack rocked a market in Yemen's mainly Shiite northern city of Saada on Wednesday, killing a civilian, a rebel group said.
The attacker, riding a motorbike, "blew himself up at the entrance of the market where there were many passersby... One civilian was martyred," the Ansaruallah (Supporters of God) rebel group said on its website.
A rebel earlier told AFP the bomber had set off his charge in the middle of the market, but the statement said he had been unable to enter and so had blown himself up at the entrance.
The defence ministry said two people had been killed and 11 others wounded, without saying who the dead were.
The rebels belong to the Zaidi sect of Shiite Islam and have controlled the northern part of Yemen since a 2004 uprising they launched against the central government.
Intermittent fighting killed thousands of people before a ceasefire was reached in February 2010.
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Lately, tensions have been brewing between the Sunni-dominated government and the Zaidis, whom authorities accuse of receiving support from Shiite-majority Iran.
Tensions have also been running high between the Zaidis and Sunni Muslim Al-Qaeda in the Arabian Peninsula, which has presence in the south.
Ansaruallah did not directly blame anyone for Wednesday's assault, but said that "Wahhabi takfiri elements (a reference to Sunni extremists) have flocked into the area of Dammaj," a town near Saada, the past few days.
Salafists and Zaidis frequently clash there, and dozens from both sides were killed last year.
"These elements, backed by suspected foreign and local parties" aim at sowing "sectarian sedition and causing internal strife," the group said.
On Monday, authorities announced they had dismantled a bomb planted in a car parked outside a Zaidi religious centre headed by a rebel leader in the Yemeni capital.
Representatives of Ansaruallah, are taking part in a national dialogue conference to draft a new constitution and prepare for elections in February.