Libyan Prime Minister Fayez al-Sarraj says his rival for power, General Khalifa Haftar, is trying to stage a coup and take Libya by force.
"He's dreaming of entering Tripoli," al-Sarraj told France 24 television in Paris Wednesday.
"This attack must be clearly condemned because it is an attempt to overthrow the (government's) legitimacy and seize power ... the destruction of the (political) process was carried out by the Khalifa Haftar, not the government of national accord and we are ready to return to the political process once conditions are met."
Haftar leads a rival government in eastern Libya. His Libyan National Army moved against al-Sarraj's U.N.-installed government last month, but has been bogged down by government forces and their allies in Tripoli's southern suburbs, unable to take the capital.
Some Libyan civilians caught in the fighting have said they don't care who wins, they just want the fighting to stop.
U.N. officials say the fighting has killed 440 people and forced tens of thousands to flee their homes. Many are staying in migrant detention centers.
Airstrikes reportedly hit one center in eastern Tripoli Tuesday, wounding two. Another report says a hole was blown in an airplane hangar housing women. A baby came within inches of being hit by shrapnel.
U.N. authorities are also investigating the suspected use of an armed drone by Haftar's forces or a possible third party supporting the general.
The U.N. says whoever used the drone or sent it to Haftar would be violating the arms embargo against Libya.
The U.N. and humanitarian aid groups say the fighting may lead to a new refugee crisis as civilians try to escape to Europe by attempting the dangerous crossing via the Mediterranean Sea.
They also fear terrorist groups, such as Islamic State, will take advantage of the chaos.