Yemeni police clashed with suspected Al-Qaeda militants in Aden Friday, arresting several, as they searched for a group that had attacked an intelligence building there, a security official said. The Interior Ministry called for a security alert in the southern port city to prevent militants from entering or smuggling in arms to threaten the economic hub of the impoverished Arabian peninsula state. The security official told Reuters clashes broke out during a house-to-house search in Aden's Saada district, launched in an attempt to arrest militants behind the attack on the city's intelligence headquarters that killed 11 people last Saturday. “Some suspects were arrested,” said the official, declining to give more details. Yemen has blamed Al-Qaeda's wing in Yemen for the attack in which militants wearing military uniforms raided the intelligence police building, killing seven security officers, three women and a 7-year-old boy, and freeing several detainees. Authorities said earlier they arrested the head of the group behind the assault. The Interior Ministry “called on security bodies to tighten their grip on Aden's coast and to keep it under constant watch to prevent the infiltration of any terrorist elements into the city or the smuggling of weapons”, the ministry website said. The ministry “reiterated the importance of safeguarding Aden province, the economic capital of Yemen, from any terrorist act”, the website added.