Government forces back by allies from the Ethiopian army raided several houses in the southern Towfiq neighbourhood where they seized caches of AK-47 rifles as well as a private hospital where they disarmed the guards, witnesses and government sources said.

"The government forces have started security operations in the capital and today's raids were part of that," a senior security official said.

"They have been given orders to collect any illegal weapon and also those conducting violent operations in the capital," he added on condition of anonymity.

The operation came a day after the Somali parliament passed a bill which effectively gives the government the right to impose martial law in a country which has been a byword for anarchy for much of the last two decades.

The vote by lawmakers gives President Abdullahi Yusuf Ahmed's administration added authority in its quest to rein in the country's warlords and their militias after the Islamists, which had ruled Mogadishu since June, fled the capital late last month.

The law allows the president to issue decrees on national security, ban unlawful demonstrations and outlaw the spreading of propaganda.