Cairo, Washington: Seven people were killed and more than 15 wounded in a suicide bomb attack on Friday that struck a market in the Yemeni city of Marib, east of Sana’a, police sources said.

The sources said it was not clear who was behind the attack which went off in a crowded market where the drug qat is sold.

Renewed fighting across Yemen is threatening to wreck a truce that had largely held since April 10 and was seen buttressing a round of UN-backed peace talks in Kuwait aimed at ending the country’s civil war.

Saudi Arabia and its Gulf Arab allies intervened in Yemen’s civil war on March 26 last year in support of the government after it had been forced into exile by the Iran-allied Al Houthi group.

US officials meanwhile said on Thursday that the Pentagon is providing military support, intelligence, ships and special operations forces to help in the ongoing operations against Al Qaida in Yemen.

The US military is helping Yemeni, Emirati and Arab coalition forces battling Al Qaida in the Arabian Peninsula who were recently able to retake the port city of Al Mukalla from Al Qaida control.

A senior US official said that American special operations forces are advising the Yemeni and coalition forces in the region, and that they are working at the headquarters level and are not near the conflict. The official was not authorised to discuss the issue publicly so spoke on condition of anonymity.

Navy Captain Jeff Davis, a Pentagon spokesman, said the US is providing “limited support” to the Arab coalition and Yemeni operations in and around Al Mukalla. He said that includes planning, airborne surveillance, intelligence gathering, medical support, refuelling and maritime interdiction.

Davis declined to discuss whether or not special operations forces were in the country. But he said the US has sent a number of ships to the region including the USS Boxer amphibious ready group and the 13th Marine Expeditionary Unit, which is embarked with the group. The USS Gravely and USS Gonzalez, both Navy destroyers, are also in the area.

“Trained and supported by an Arab coalition led by Saudi Arabia and the UAE, Yemeni government forces and resistance fighters have retaken Al Mukalla and continue their offensive against AQAP in eastern Yemen,” said Davis. “AQAP remains a significant security threat to the United States and to our regional partners and we welcome this effort to specifically remove AQAP from Al Mukalla and to degrade, disrupt and destroy AQAP in Yemen.”

Late last month forces loyal to Yemen’s internationally recognised government drove AQAP fighters from Al Mukalla, a year after they captured it. Al Mukalla had been their stronghold.

Al Qaida had gained ground amid the chaos that has reigned in Yemen since 2014 with Yemen’s Al Houthi rebels fighting the internationally backed government and its allies with the Saudi-led coalition.

Security officials and witnesses also said on Thursday that Al Qaida militants in Yemen were pulling out of Zinjibar and Jaar, two coastal cities east of the key southern port of Aden, following tribal-led negotiations.

The officials spoke on condition of anonymity because they were not authorised to talk to reporters while the witnesses requested anonymity out of safety concerns.