'We have seized a large number of weapons,' said Major Ken Roberts. 'We feel we have taken a significant number of weapons off the streets and out of the market.'
The US military has pledged to clean up the anarchic Somali capital to pave the way for future United Nations peacekeepers, who are expected to replace the present 32,000-strong task force.
About 900 Marines in armoured vehicles moved in after daybreak to seal off the sprawling Bakara market, a maze of dusty streets where a thriving arms bazaar sprang up after the overthrow of President Mohamed Siad Barre two years ago. No shots were fired and the Marines found one warehouse packed with grenades and ammunition for howitzers and mortars. Psychological warfare specialists in helicopters boomed out explanations to the public from loudspeakers.
The operation, codenamed Nutcracker, was the biggest of its kind since the American-led task force came ashore in Mogadishu on 9 December. The market lies in an area nominally controlled by one of the leading Somali warlords, Mohamed Farah Aideed, and a US spokesman said it was believed to be the largest weapons bazaar in Somalia. It offered a bewildering range of armaments, from pistols and grenades to assault rifles and anti-aircraft guns.
On Friday 450 Marines closed down a smaller arms market, known as the Argentine market, in north Mogadishu, held by forces loyal to Mr Aideed's bitter rival Ali Mahdi Mohamed.
Before the operation, gunfire would regularly crack out as customers fired in the air to test weapons on display. Five days ago, a Somali working for a foreign news agency was shot dead when he tried to stop a robbery in another part of the market specialising in food and household goods.
Insecurity still haunts the capital, even though foreign troops have rapidly taken control of inland famine-hit towns to make sure that relief convoys can deliver food to the starving.
Nour Abdukadir, a Somali working for the relief agency Goal-Ireland, was killed by crossfire outside a feeding centre near Mogadishu's Green Line where rival clans fought a gunbattle on Sunday.
The US military has begun to exert a tighter grip on Mogadishu, using combat units returning to the capital after their initial deployment to the interior.