Islamists take key Somali town...

Is Somalia going to fall this week?

Militant Islamist fighters captured a strategic town north of Mogadishu on Sunday, leaving government forces isolated in pockets of the country's capital and central region after two weeks of heavy clashes.

In a sign of some disarray among militant ranks however, a former warlord and powerful opposition leader defected to the government side over the weekend.

President Sheikh Sharif Ahmed's United Nations-backed government -- the 15th attempt to establish central rule -- is struggling like predecessors to contain powerful insurgents, currently led by hardline militant al Shabaab.

"Al Shabaab captured Jowhar after serious fighting on Sunday morning," resident Ismail Farah told Reuters. "At least seven people including four civilians died."

Jowhar, Ahmed's hometown, is 90 km (56 miles) from Mogadishu and links it to the volatile central region where local sources say 68 people have been killed in clashes between al Shabaab and a moderate Islamist group since Friday.

Over the past two weeks, fighting in southern Somalia has killed at least 172 civilians and wounded 528 others, according to a local rights group.

Somali Security Minister Omar Hashi Aden said the militants were being supported from outside. He has previously accused Eritrea of arming the insurgents, a charge Asmara denies.

"They are fighting in Mogadishu, and central Somalia. They have also started a war in Jowhar. They are economically and militarily supported ... it is not cheap to sustain fighting."