Liberian President Charles Taylor declared a state of emergency following reports of fighting near the capital between government and rebel forces, which has sent thousands fleeing.
President Taylor's address to the nation came hours after gunshots near the capital, Monrovia, suggested an armed rebellion was gaining ground.
Without giving details of the clashes, he said it was his duty, as president and commander in chief of the armed forces, to restore peace and security to the Liberian people.
Information Minister Reginald Goodridge said government forces had been fighting to repel a rebel attack late Thursday on Klay Junction, only 35 kilometers down a main road from Monrovia.
A rebel spokesman, William Hanson, said late Friday that forces known as the LURD, or Liberians United for Reconciliation and Democracy, had taken Klay, and were poised to take the capital within days.
Refugees arriving in Monrovia Friday said they were fleeing Klay because of gunfire. Tens of thousands of refugees have been camped at Klay since fleeing earlier clashes.
Monrovians fear a repeat performance of the bloody street battles that struck the capital during the civil war from 1989 to 1996. These ended when former warlord Charles Taylor was elected president in 1997.
For the last two years, forces loyal to Mr. Taylor have been engaged in sporadic clashes with rebel factions in the north.
But this is the closest they have gotten to the south coast capital since the latest episode of civil war broke out in mid-2000.
Mr. Taylor said in his address that the international arms embargo on his country had encouraged the current mayhem.
A government spokesman added that after the current incursions, Liberia declared the right to protect itself under Article 61 of the U.N. charter.
Although the war officially ended in neighboring Sierra Leone last month, Liberia, accused of fueling the conflict by trading guns for diamonds, is still under U.N. sanctions.
Mr. Taylor's speech comes a day ahead of the first visit to Sierra Leone by British Prime Minister, Tony Blair, on Saturday.
Soldiers from the former colonial power have played a key role in fighting back Liberian-supported rebels and training a new army there.
Liberia was founded by freed American slaves as a haven of liberty in the 19th century. But in recent years its name has become more associated with anarchy and bloodshed.