Somalia's president urged the international community Monday to help his country drive out hundreds of foreigners who are believed to be fighting alongside radical Islamic insurgents in the country.

President Sheik Sharif Sheik Ahmed made the appeal as a radical Islamic group claimed responsibility for a suicide bombing that killed seven people over the weekend.

The smouldering remains of a vehicle used in a suicide attack at a government military base are seen in the Somalian capital, Mogadishu, on Sunday. A suicide bomber killed a number of guards at the military base, a government official said, an attack that comes after two weeks of intense fighting in war-torn Mogadishu. (Farah Abdi Warsameh/Associated Press)

The political leader of the radical group al-Shabab, Sheik Husein Ali Fidow, said a teenager carried out the attack on a military base in the Somali capital Sunday. Six guards and a civilian were killed, the government said.

Authorities suspect the bomber was one of some 300 foreigners — from countries including Pakistan, Yemen and the United States — that the UN and others say are fighting alongside Islamist insurgents.

"The world should help us get rid of the foreigners who are fighting against the Somali government," Ahmed said. "Otherwise the country and the government will be in danger."

More than 150 people have been killed and hundreds injured in the past two weeks, and the U.N. said the violence has prompted 57,000 Somalians to flee the city. Somalia has not had a functioning government since 1991, when warlords overthrew a socialist dictator and then turned their clan-based militias on each other.

Somalia's two main Islamist insurgent groups, the Islamic Party and al-Shabab, formed an alliance a month ago to overthrow Somalia's new, Western-backed government, headed by their former ally President Sheik Sharif Sheik Ahmed. They consider Ahmed a traitor for signing a peace deal that paved the way for him to become president earlier this year.

The United States worries that Somalia could be a terrorist breeding ground, particularly since Osama bin Laden declared his support for the Islamists. The U.S. accuses al-Shabab of harbouring the al-Qaeda-linked terrorists who allegedly blew up the U.S. embassies in Kenya and Tanzania in 1998.

Somalia's information minister has warned residents to remain vigilant.

"We have information that al-Shabab is planning more suicide attacks. Therefore, I warn the residents and government forces to be alert," Farhan Ali Mohamed said.