The government said Tuesday its forces still held the country's main international airport, but diplomats said rebels had overrun an American-managed rubber plantation on its outskirts.
The government acknowledged that airlines had halted flights to Robertsfield International Airport, 35 miles from Monrovia, the capital.Fearful residents fled the city and some government soldiers abandoned key posts before the rebel advance.
Off the West African nation's coast, a U.S. Navy flotilla carrying 2,000 Marines stood ready to evacuate Americans and other foreigners.
President Samuel Doe remained at his presidential mansion in Monrovia, shielded by about 1,000 Israeli-trained troops.
Doe continued last-ditch efforts to end the 6-month-old civil war, meeting with church leaders who have offered to act as intermediaries.
The Liberian president begged the United States and other friendly countries "to come to the aid of the Liberian people."
"It is the wishes of the people of this country that America can do something to stop the bloodshed," he said Monday.
In Monrovia, people of the Mandingo and Krahn tribes loyal to Doe - himself a Krahn - packed their belongings to flee the city. They said they feared reprisals by rebels, who appeared to be closing in on the city of about 400,000 residents.
A U.S. State Department spokeswoman said 71 Americans, including 33 U.S. Embassy officials and their families, were evacuated Monday on a chartered flight.
The spokeswoman, Margaret Tutwiler, said in Washington that about 70 U.S. officials and 1,200 private American citizens remained in Liberia.
Tuesday, diplomats said rebels lobbed mortars and fired machine guns as they poured into the American-managed rubber plantation from across the Farmington River, the last natural barrier between the rebels and Monrovia.
The BridgestoneFirestone Inc. rubber plantation adjoins Robertsfield airport.