The Nigerian-led ECOMIL peacekeeping force was rebuffed Friday when it attempted to reopen talks with the rebels, AFP reported.
With three days remaining before President Charles Taylor is due to step down, tensions in the harbour-city remain high.
In order to provide humanitarian assistance to the war-ravaged city, ECOMIL needs to gain control of the port. Monrovia is now home to some 250,000 displaced people living in appalling conditions suffering acute shortages of food and a lack of medical supplies.
Basic utilities such as electricity and drinking water have been severely disrupted by heavy fighting between troops loyal to Taylor, an indicted war criminal, and fighters from the rebel group Liberians United for Reconciliation and Democracy.
Despite the rebels rebuttal, an emergency convoy from the International Committee of the Red Cross and Medecins Sans Frontieres managed to cross the frontline Friday and enter the port area.
The teams found some 60 wounded civilians and fighters receiving basic medical attention in an abandoned brewery.
Separately, a team of US military experts visited the rebel-held zone and negotiated the evacuation of two American girls.
Shadya Monger, aged 7, and her 17-year-old half-sister Princess Sunnie, who had sought refuge in a Protestant church were taken to the government-controlled side, where the US embassy is located, unidentified US sources told AFP.
Taylor has promised to relinquish power on Monday and travel to Nigeria where he has been offered asylum.
On Thursday, he sent a message to Liberia’s parliament claiming he was the victim of an "international conspiracy", meaning he was no longer able to continue as President.
“They have prevented me from carrying out my constitutional responsibility of defending the country, providing essential social services to the people," Taylor said, referring to UN sanctions and an arms embargo in place since 2001.
The Liberian parliament approved Taylor's resignation Thursday by 46 votes to one. It also approved his recommendation that Vice President Moses Blah be appointed his successor.
Fighting may continue
Still, LURD opposition to Blah’s appointment as head of the provisional government may yet result in a fresh bout of fighting.
“We cannot leave the Liberian people to Moses Blah, who is a general in Taylor's army,” LURD's civilian deputy secretary general Sekou Fofana told AFP. “We need a neutral civilian to lead the transition.”