SANAA, Sept. 28 (Xinhua) -- Shiite Houthi rebels were attacked by a suicide car bombing in Yemen's central province of Marib on Sunday which left at least 15 people died, security and tribal sources said.

The rebels were gathering to prepare for a patrol on the highway linking Marib to the capital Sanaa when an al-Qaida member committed the suicide car bombing against them, sources said, adding that about 20 people were wounded in the explosion.

The al-Qaida in the Arabian Peninsula (AQAP) claimed the attack in a statement posted on its website and vowed more attacks against the Houthi group in the future.

Dozens of people were killed in sporadic clashes between the Houthi rebels and al-Qaida militants in Yemen's southern regions in the past few weeks, when the Houthi group launched military offensive in Sanaa and eventually took over the capital.

The Houthis, based in the country's far north, tightened their control in Sanaa and started further presence in the southern regions after they signed a ceasefire deal with the government last week.

However, security in the Arab country deteriorated as clashes had paralyzed the central government.

On Saturday night, the U.S. embassy in Sanaa was attacked by a rocket which wounded five security guards. The AQAP then claimed the attack.

The U.S. administration on Thursday ordered a reduced diplomatic presence in Yemen and warned citizens against travel to the Arab country, citing "changing" and " uNPRedictable" security situation there.