A column of some 20 French tanks and troop carriers rumbled through the streets of the Somali capital, where 23 UN soldiers from Pakistan were killed in a battle with Gen Aideed's men on Sunday. The tanks deployed at the port and airport.
The French forces came from the southern town of Baidoa, known as the 'city of death' during last year's famine.
A US task force - aviation units from the 10th Mountain Division and the 101st Air Assault Division - moved into the capital from duties at the airbase at Bale Dogle, about 110 km (70 miles) west of the city.
In Washington, officials said the US was sending AC-130 attack aircraft possibly to retaliate for the killing of the Pakistanis.
The few aid workers still in Mogadishu retreated behind sandbagged walls yesterday while UN troops increased security at key installations. Turkish tanks took up position outside the headquarters of Unosom (the UN Operation in Somalia) and aid workers said the United Nations had told them in confidential briefings to expect 'collateral damage' from a military strike. The UN also said it could not guarantee their safety.
The US relief organisation Care evacuated its two remaining international staff yesterday, and the Save the Children Fund moved into a well-protected compound further away from Gen Aideed's residence.
UN officials also moved out of their headquarters in central Mogadishu to the heavily fortified Unosom military headquarters on the outskirts.
The UN's special envoy, Admiral Jonathan Howe, played down predictions of imminent military action and did not rule out a settlement to the crisis. He said lines of communications remained open between Unosom and Gen Aideed.
'We are not out to kill anyone, there have been too many Somalis killed already,' he said. 'I can't tell you what to expect over the next few days, but I hope we have peaceful reconciliation.'
The Turkish commander of UN forces in Somalia, Lieutenant-General Cevik Bir, appealed through UN radio for the return of one Pakistani soldier still missing. He told Somalis Gen Aideed's faction and its allies in the Somali National Alliance wanted to 'bring back the anarchy and death, starvation and poverty you experienced before'. 'You have suffered enough. You must act to save the progress made toward true freedom and renewed prosperity,' he added.
Germany sent another contingent of troops to Somalia yesterday despite growing fears for their safety and an opposition bid to have the mission ruled unconstitutional. The Defence Ministry said 140 troops were due to leave last night to reinforce an earlier advance party of 145.
Chancellor Helmut Kohl's government had agreed earlier yesterday to stick with plans to send 1,700 troops to war-stricken Somalia by mid-August.