The Muslim leaders who rule much of southern Somalia claimed authority throughout the country Thursday, underscoring the weakness of Somalia's U.N.-backed interim government.

Sheikh Sharif Sheikh Ahmed, leader of the militia's executive council, made the comments while officially announcing the restructuring of the Islamic Courts Union. The group added dozens of new members over the weekend who lead sharia courts throughout Somalia.

Ahmed refused to take questions from the media.

Thursday's development comes a week after the Islamic union agreed to recognize the interim government and stop all military action — a move that signaled a willingness to accommodate the desires of the international community. The U.N.-backed interim government carries little sway in Somalia. Its operations are restricted to Baidoa, 90 miles from the capital.

In the days since the agreement was signed, the militia replaced Ahmed as its top leader with a radical Islamic cleric, Sheikh Hassan Dahir Aweys, who is on the U.S. terrorist watch list as a suspected collaborator with Al Qaeda.

And on Wednesday, the group said it would not consult with anybody on how it runs the capital, Mogadishu. Ahmed was responding to criticism that the group violated the deal to stop military action by seizing a clan-held checkpoint just outside Mogadishu in a battle that killed six people earlier this week.

"We are responsible for the security of the capital, and those who say we broke the agreement did not understand what the agreement was about," Ahmed said.

Islamic militiamen dismantled another checkpoint near Mogadishu's weapons market Thursday without a fight.

Somalia has been without an effective central government since warlords toppled dictator Mohamed Siad Barre in 1991 and then turned on each other, carving much of the country into armed camps ruled by violence and clan law. Many of the capital's residents applauded the Islamic group for forcing the warlords from Mogadishu, despite concerns the militia may try to remake Somalia into a theocracy akin to Afghanistan under the Taliban.

On Wednesday, hundreds of people who live near the checkpoint battleground began fleeing their homes for fear of renewed fighting.

The Islamic militia broke up the checkpoint just outside southern Mogadishu on Tuesday. By Wednesday, the clan had regrouped and deployed hundreds of fighters to the area.

"We have left our house because we are afraid to be trapped between the opposing militias," said Sahra Yusuf, a mother of six.

Militiamen loyal to Habar Gidir clan leader Abdi Hassan Awale were massed just 550 yards from Islamist fighters, said Hassan Fidow, whose restaurant is nearby. Awale, a former police chief, is also known as Abdi Qeybdiid.

Washington has long-standing concerns that Somalia will become a refuge for members of Usama bin Laden's terror network, much like Afghanistan did in the late 1990s. The U.S. has accused the Islamic militia of harboring al-Qaida leaders responsible for deadly 1998 bombings at the U.S. embassies in Kenya and Tanzania. The U.S. backed the warlords in their fight against the Islamic militia.