Islamic insurgents in Somalia have shelled the main market in the capital Mogadishu, killing at least 13. As Nick Wadhams reports from Nairobi, the transitional government's security chief says his forces have become powerless to stop the rebels.

Sheikh Qasim Ibrahim Nur made the comments to The Associated Press, telling the news agency that the transitional federal government is now "powerless to resist" Islamic fighters.

He told the news service that 80 percent of the country is unsafe and that insurgents are planning a massive attack. It was not clear if the market shelling was part of that expected offensive.

The comments were official recognition of what has been apparent for months. Nearly a year after government troops backed by the Ethiopian army pushed Islamic militants from Mogadishu, the fighters have regained much of their power, and there are growing concerns that Islamic groups are spreading well beyond Mogadishu. Reports from Somalia in recent days suggest that Islamic militants have been targeting towns across the country.

Said Tahliil is a Somali journalist.  He spoke to VOA by phone from Mogadishu, where he witnessed the market attack.

Tahliil tells VOA that the Baraka market was attacked with mortars.  He said 13 people are confirmed dead and another 40 people were wounded in the attack.  He says there is heavy fighting in Mogadishu, and people are fleeing because they are afraid the new wave of fighting will reach their homes.

Somalia has been without an effective government since 1991, when a coup ousted dictator Mohammed Siad Barre. Troops from Somalia and Ethiopia have been battling Islamic insurgents for months, and the United Nations now says the country is suffering from the world's worst humanitarian crisis.

Early this week, the United Nations asked for $403 million to fund relief efforts in Somalia.  The United Nations says about 1.5 million people are in desperate need of aid.