A new offensive against Islamist militias is a sign of hope for Somalia's fragile western-backed government.

Transitional Federal Government (TFG) soldiers are preparing to launch an offensive against Islamist militia in Mogadishu. Photograph: POOL/REUTERS

Long-suffering residents of Mogadishu are steeling themselves for a new round of fighting as the western-backed transitional federal government (TFG) prepares to launch an offensive to expel Islamist militiamen from the Somali capital. Yet grim though the prospect is of renewed violence, the looming attack is a sign the tide may be turning in Somalia: the "good guys" are fighting back.

Speaking in London on Tuesday, Sheikh Sharif Ahmed, Somalia's president, declined to detail his plans to wrest control from the hardline al-Shabaab militia, which currently holds most of the city. Asked about reports that the US military may provide air cover during the forthcoming offensive, he said he would welcome any support the Americans and British chose to offer.

Gordon Brown pledged British support for the transitional government of Somalia yesterday as its Western-backed president prepared to launch an offensive to seize control of Mogadishu from al-Qaeda linked fighters.

Britain has offered £5.7 million to fund the build-up of an official Somalian security force and has dramatically increased British aid to Somalia tenfold to £30 million since Sheikh Sharif Ahmed was installed as president last year.

President Ahmed said he welcomed foreign support as he targets al-Shabaab, the fundamentalist movement that has appealed for British Somalis to train as suicide bombers.

Sacks of food in a warehouse in Mogadishu. A United Nations report suggests an overhaul in the food distribution system.

As much as half the food aid sent to Somalia is diverted from needy people to a web of corrupt contractors, radical Islamist militants and local United Nations staff members, according to a new Security Council report.

The report, which has not yet been made public but was shown to The New York Times by diplomats, outlines a host of problems so grave that it recommends that Secretary General Ban Ki-moon open an independent investigation into the World Food Program’s Somalia operations. It suggests that the program rebuild the food distribution system — which serves at least 2.5 million people and whose aid was worth about $485 million in 2009 — from scratch to break what it describes as a corrupt cartel of Somali distributors.

In addition to the diversion of food aid, regional Somali authorities are collaborating with pirates who hijack ships along the lawless coast, the report says, and Somali government ministers have auctioned off diplomatic visas for trips to Europe to the highest bidders, some of whom may have been pirates or insurgents.