Sunday's suicide bombing was the second deadly attack in the port city of Mukalla in four days. The city of 200,000 was recently recaptured by government troops from al-Qaeda militants, with support from Saudi Arabia and the United States. But "Islamic State" (IS) jihadis are claiming responsibility for the two recent attacks.

The bomber walked into a police recruitment center and detonated his bomb amid a crowd of recruits.

There are also conflicting reports as to how many bombers were involved in Sunday's attack, but the French news agency AFP reported that a second explosion after the initial attack targeted General Mubarak al-Oubthani, a regional commander, who had left his office to inspect the damage done by the initial bomber.

Body guards killed

All of his guards were killed, but Oubthani escaped with only minor injuries, an official said.

Militants had also attacked an army post on Thursday, killing 15 Yemeni troops outside Mukalla. An IS militant reportedly blew up an explosives-laden vehicle at an army base on the city's eastern outskirts.

Last week's suicide attack also targeted a high-ranking officer - the residence of the regional commander, General Faraj Salmeen, but he escaped unharmed, officials said.

On Friday, the general boasted that his forces had captured about 250 al-Qaeda militants since retaking Mukalla and nearby coastal communities. He said the captives included a jihadi commander for the cit of Shihr, about 35 miles (60 kilometers) to the east.

Al Qaeda was driven out of Mukalla last month with the backing of Emirati and Saudi special forces.

The US Defense Department said last week that a "very small number" of US military personnel had also been deployed around Mukalla to support the operation.

The US Navy has warships nearby, including the USS Boxer amphibious assault vessel and two destroyers.

An IS statement posted online Sunday claimed responsibility for the day's attack in the former al-Qaeda stronghold.

"Brother Abu al-Bara al-Ansari... detonated his explosives belt at a gathering of the apostates of the security forces," it said.

bik/sms (AFP, Reuters, AP, dpa)