MONROVIA, Liberia (AP) -- U.S. military helicopters landed scores of American troops at Liberia's main airport Thursday, significantly bolstering American involvement in the warring country.
Nine helicopters flying in formation settled on the tarmac, as two more hovered overhead.
Scores of American troops jumped out wearing flak vests and helmets and armed with rifles.
BBC's got some more details:
http://news.bbc.co.uk/1/hi/world/africa/3149255.stm West African peacekeepers have entered rebel-held parts of the Liberian capital, Monrovia, for the first time, as some 200 US Marines have started arriving.
Two armoured personnel carriers with Nigerian troops, guns at the ready, crossed the former frontline of the Old Bridge as rebels cleared roadblocks to let them through.
The BBC's Barnaby Phillips in Monrovia says that civilians waved and cheered as the peacekeepers came into view.
Rebel forces anoounced that they would surrender the port area to West African peacekeepers at 1200 GMT on Thursday.
Our correspondent says there is a second day of chaos around the port as thousands of people loot food from warehouses there.
The US troops are supposed to help the Nigerian-led peacekeepers secure the port and deliver desperately needed humanitarian aid to the city.
But civilians are worried that government fighters may try to move in as the rebels withdraw, leading to renewed fighting.
Meanwhile, new interim President Moses Blah is expected to go to neighbouring Ghana on Thursday to meet rebel leaders.
Nine helicopters carrying scores of US troops landed at Robertsfield airport, some 50 kilometres (30 miles) from central Monrovia on Thursday morning.
The US has repeatedly insisted that the main peacekeeping role in Liberia would be played by the West African force, which currently consists of less than 800 Nigerian troops.
But following talks with the Nigerians, the US agreed to provide some logistical and combat support.
Once the rebels leave the port, US troops will ensure that the channel to the port is free of obstacles and US aircraft will support the Nigerians.
Famished
Our correspondent says that on Wednesday, rebel soldiers fired in the air and beat the looters with sticks, but could not prevent the theft of a significant proportion of UN stocks.
The rebel Liberians United for Reconciliation and Democracy (Lurd) group said they had brought the area under control.
"We have now deployed security there, which will stay there until 1200 tomorrow afternoon, when we will hand over the Bushrod Island and the port to peacekeeping force," Lurd official Sekou Fofana told AFP news agency.
The rebels' presence has stopped humanitarian aid reaching hundreds of thousands of famished refugees in Monrovia.
An emergency relief co-ordinator in Liberia, Carolyn McAskie, said the World Food Programme had a supply ship anchored offshore, as well as food aid in the region ready to be flown in.
But she warned that more peacekeepers were needed.
Another battalion of Nigerian troops is due to arrive in Monrovia in the coming days and the Pentagon said the aim was for the US reaction force to stay in Liberia for a short a time as possible.
However US officials left open the possibility that they would stay there as long as they were needed.
Liberian President Charles Taylor flew into exile in Nigeria on Monday as part of attempts to end years of conflict.
Interim President Moses Blah - Mr Taylor's former deputy - is set to rule Liberia until October.
Lurd rebels have rejected his appointment but say they will respect the ceasefire.