They were being flown today to the Liberian capital, Monrovia, before their scheduled return here tomorrow.
The Liberian capital bears the scars of war and devastation.
Most of the shops and office buildings in the Liberian capital have been looted and many destroyed since the fighting began.
The new fighting dampened hopes for a peaceful resolution to the factional dispute that has turned the Liberian capital into a war zone.
One option is to fly Army forces into Monrovia, the Liberian capital.
Guns have fallen silent in Monrovia, but residents in the Liberian capital are still starving, aid officials and refugees say.
Virtually no business in the Liberian capital has been spared a thorough looting by militia groups fighting there.
The force was expected to move into the besieged Liberian capital later this week.
The Administration is especially worried that important United States communications installations outside the Liberian capital could be damaged by the escalating violence, the officials said.
A10 Fighting continued to threaten refugees in the Liberian capital.