Liberian army chief General Benjamin Yeaten said forces from the Liberians United for Reconciliation and Democracy (LURD) "are still shelling our positions".
He said the west African country's second port Buchanan, overrun by the smaller Movement for Democracy in Liberia on Monday, was also witnessing fierce battles.
"Our forces are making good progress there," he said. "We have retaken the port."
His comments came as Nigerian General Festus Okokwo arrived in Liberia on Wednesday to conduct an evaluation mission before the despatch of peacekeeping troops.
Okokwo is the leader of the proposed first contingent of troops offered by Nigeria, west Africa's regional powerhouse.
Nigeria has pledged to send two battalions totalling around 1,500 men to Liberia, where rebels have closed in on the capital Monrovia in fighting against forces loyal to President Charles Taylor.
"There are bodies all over the place. Dozens of people have been killed."
-- A resident of Buchanan
The United States has also pledged to support a west African force and sent three warships to the region, but the White House has said it will not put US boots on the ground until a ceasefire is in place and Taylor leaves power.
In a related development, the US State Department's point man on Africa, Walter Kansteiner, arrived in the Guinea Bissau capital of Conakry on Wednesday to press the government to stop its alleged support of rebels in Liberia, sources said.
Kansteiner, the assistant secretary of state for African affairs, met Guinean Foreign Minister Francois Fall and was expected to meet Prime Minister Lamine Sidime later.
Guinea denies supporting LURD who have been fighting Taylor's government since 1999.
Dozens of civilians have been killed in fighting for Buchanan, residents said.
"There are bodies all over the place. Dozens of people have been killed," said one resident by telephone, who did not want to give his name. "The wounded are on the streets and there is no way to treat them."
People are desperate to get
away from the fighting
In the meantime, the humanitarian situation in the country is reaching dire proportions.
Nearly 52,000 displaced people are crammed into a 35,000-seater stadium in the war-ravaged capital Monrovia and are facing starvation, a humanitarian official said on Wednesday.
"Right now there are 51,937 people here," said James Folokula of the Liberian Refugee Repatriation and Resettlement Commission.
"We can't take in any more now." Sanitary conditions in the camp were also deteriorating, he added.
Folokula said humanitarian workers are now turning desperate civilians away from the Samuel Kanyon Doe stadium, the largest camp for displaced people in the capital.
No emergency food rations have been distributed by the International Committee of the Red Cross since the conflict engulfed the capital on July 18.
Folokula said ICRC officials are to renew attempts to distribute food aid.
But malnutrition and starvation is becoming a serious problem in the camp, he said, although foreign agencies have managed to provide safe drinking water, averting a threatened cholera epidemic.