Sana’a: Suspected Al Qaida militants have seized control of a town in southwest Yemen, hours after Al Houthi rebels overran a nearby provincial capital, a security official said on Thursday.

Five policemen were killed in the overnight offensive by militants on the town of Udain, 20 kilometres west of the now rebel-controlled Ibb, the security official and local sources said.

The gunmen attacked the police headquarters, which was set ablaze, and the offices of the local government, as well as the post office.

Al Qaida is active in several Yemeni provinces, mainly in the south and southeast, where repeated government military campaigns drove the network’s militants out of key cities they once controlled.

The attack on Udain appeared to be in retaliation for the Al Houthi rebels’ control of Ibb, a local official said.

Already in control of Sana’a and the strategic port city of Hodeidah, the rebels on Wednesday appeared to have taken control of the Dhamar and Ibb provinces, security officials said.

Just as in Sana’a and Hodeidah, the rebels faced no opposition as they entered the two provinces and set up checkpoints, the officials said.

The rebels have been taking advantage of a power vacuum in Yemen to seize control of significant areas, threatening the authority of the Sunni-led central government.

But their expansion threatens of an open confrontation with Al Qaida.

Deadly fighting broke out on Tuesday when the Al Houthis tried to expand out of the town of Rada’a in central Baida and clashed with Al Qaida militants.

Five rebels, six suspected Al Qaida militants and a civilian were killed during the fighting in Rada’a, a security official and tribal sources said on Wednesday.

Impoverished Yemen, a key ally in US efforts to combat Al Qaida, has been wracked by political turmoil and sporadic violence since an uprising toppled strongman Ali Abdullah Saleh in 2012.