The army of Liberian President Charles Taylor has been put on "maximum alert" on all fronts following attacks by two rebel groups and in expectation there may be another attack on the capital, the deputy chief of staff of government forces told reporters.
"Our troops are on the highest level of alert. For the last four days we have increased the level of security," General Benjamin Yeaten said.
"We are expecting the next 48 hours to be decisive," he predicted.
"We are hearing shelling from Bomi Hills. According to our intelligence we learnt that LURD dissidents have been preparing to attack Monrovia again," Yeaten said.
A rebel leader denied that an attack on the capital was imminent.
Chayee Doe, Deputy President of the main rebel movement, Liberians United for Reconciliation and Democracy (LURD), said that Taylor's forces had violated the ceasefire on several fronts, a claim which could not be independently verified.
"Today and since last week we have been attacked in Lofa county [north], they are the ones violating the ceasefire.
"We have no plans to attack the capital, but if they continue to attack us we will fight back. We have held the ceasefire."
Liberia has been wracked by almost non-stop civil war since the 1990s, turning it into one of the world's poorest nations.
A tenuous ceasefire agreement was eventually signed on June 17, providing for "comprehensive peace talks" within 30 days on the establishment of a transition government from which Taylor would be excluded.
Warlord-turned-president Taylor, who now controls only a fifth of his country, has agreed to step down and accept asylum in Nigeria but only once an international peacekeeping force is in place.
But rebels from the LURD, who have besieged the capital, have demanded his immediate resignation.
The Economic Community of West African States (ECOWAS) on Wednesday announced its intention to quickly send up to 1,500 soldiers to Monrovia, where a US military assessment team arrived earlier this week.
"Any troop deployment before the departure of Taylor shall be viewed as a means to prop up Taylor's dying regime and to further prolong the crisis," LURD said in its statement.
More than a dozen years of conflict in Liberia have claimed at least 250,000 lives and spread chaos in west Africa, where the fighting has fuelled a humanitarian crisis.
US military experts are currently touring the country to assess humanitarian and security needs in Liberia, which was set up in the nineteenth century as a homeland for America's freed slaves.
There have been repeated calls for US help in setting up a peacekeeping force but US President George Bush has so far refused to make any commitments or promise troops for the mission.
Washington did not want to overstretch US forces, already busy on manpower-intensive missions in the former Yugoslavia, Afghanistan and Iraq, Bush said.
Nigeria, Mali and Ghana have already pledged to send 1,500 peacekeepers to the war-torn nation.
Liberian Defense Minister Daniel Chea told AFP that the government supported the ceasefire.
"We believe in the ceasefire and support the peace effort in Accra, but we have been attacked. We don't want to get involved in full-force fightings. We believe our people deserve peace. They are only trying to get us involve in undermining the ceasefire and we are not going to be part of such efforts."