(updates toll, adds claim of responsibility)

ADEN, May 15 (Reuters) - A suicide bomber blew himself up in the southern Yemeni city of Mukalla on Sunday in an attack claimed by Islamic State, killing at least ten recruits and wounding 15 as they lined up at a police headquarters, a security source said.

It was the second deadly blast to hit the city, which was a hub for al Qaeda before the group was pushed out in a military offensive last month. urn:newsml:reuters.com:*:nL5N189395

In a message on its online news agency Amaq, Islamic State said the attacker was a "martrydom-seeker" who had detonated his explosive belt.

Al Qaeda militants took advantage of more than a year of war in Yemen to carve out a mini-state stretching across much of the southern coast but an attack by government troops backed by the United Arab Emirates reversed many of their gains.

Their militant rivals in Yemen's branch of Islamic State rose last year and have launched a series of suicide attacks on all parties to Yemen's tangled conflict.

Saudi Arabia, the UAE and other Arab countries intervened in Yemen's civil war in March 2015 in support of the internationally recognized government, which had been swept into exile by Yemen's Houthi movement, an ally of Iran.

The mostly Gulf Arab military coalition fear the Houthis are acting as proxies for Tehran - something the group denies - and their fight has split Yemen's army and enabled militant groups to carry out dozens of bombing and shootings.

Al Qaeda in the Arabian Peninsula (AQAP) and Islamic State view the Arab coalition as a pawn of the West and see the Shi'ite Muslim Houthis as apostates deserving death.

The U.S. military announced last week it had deployed a small number of personnel to Yemen to aid in the fight against AQAP, its first troop presence in the country since the Houthi takeover, though its campaign of unmanned drone attacks on AQAP members continued unabated throughout the war. urn:newsml:reuters.com:*:nL2N1831FM

(Reporting by Mohammed Mukhashaf; Writing by Noah Browning; Editing by Janet Lawrence) ((noah.browning@thomsonreuters.com;))

Keywords: YEMEN SECURITY/BLAST