Story highlights Government says commanders who fire on civilian buildings will face charges

Rockets reportedly struck the airport and at least two people were killed

Libyan government says it may request international troops to help stop the violence

U.N. removes its staff in Tripoli for first time since revolution

Fighting continued Monday as rival Libyan militias battled for Tripoli International Airport and the interim government said it was considering asking for international military help.

In a statement aired on a private Libyan television channel, one of the three main Zintan groups in Tripoli said that at least two members of the force defending positions at the airport were killed in a rocket attack. Al-Qaaqaa brigade said at least three other people were wounded.

A photo posted on several Zintan Facebook pages showed a makeshift clinic set up inside the airport's main terminal.

CNN could not independently verify when the image was taken.

The government in a written statement said early Tuesday that it discussed at an emergency session "a potential request for international forces to solidify the state's capabilities" at an emergency session.

While Libyan officials have called for calm, the government is weak and militias outnumber and outgun its security forces. Many of the armed groups are on the state's payroll.

These circumstances make it very difficult for the government to gain control over this latest increasingly volatile and violent situation.

Still the government on Tuesday called for an immediate halt to the fighting and for the militias to withdraw within a week at least 20 kilometers (12 miles) from the airport. It said any commander that orders attacks on civilian facilities, including the airport, will face charges of murder.

A resident who lives near the airport told CNN families in the area are fearful they will be killed or injured by what appears to them as indiscriminate shelling.

The Libyan government statement said peacekeepers might give it a chance to build a suitable army and police force.

More rocket attacks

Local media reported earlier Monday that rockets had hit the airport. A CNN crew could hear sporadic gunfire and explosions in the direction of the airport.

The government said the customs building, maintenance building and some national security department planes had been destroyed. It also said 90% of the airliners parked there had been damaged as had the control tower. The damage to the planes, many of which belong to the two national airlines, is in the hundreds of millions of dollars, the government said.

The United Nations announced that it had evacuated its staff.

"This is a temporary measure," the United Nations said in a written statement. "Staff will return as soon as security conditions permit. The United Nations, which stood by the Libyan people in their revolution in 2011, will not abandon them as they seek to build a democratic state."

It was the first time the U.N. staff in Tripoli had left since the revolution.

The U.S. embassy updated its security message for Americans in the country, cautioning them to stay away from the airport, Airport Road and another nearby street. It said it could only provide limited emergency services to U.S. citizens.

No air traffic

All flights in and out of the airport have been suspended.

Brigades from the Zintan militia have controlled the airport since the Libyan civil war in 2011. Other militias have tried to wrest control of the airport from the Zintan brigades for years.

Armed vehicles gathered in the area overnight before fighting broke out around dawn Sunday, witnesses said. Nine people were killed that day and 25 others wounded, the government said.

Tensions remain

Even though Libyans successfully toppled the 42-year rule of Moammar Gadhafi in 2011, the country is far from stable. Armed militias are now the biggest challenge.

The international community has largely agreed that the key to resolving Libya's crisis is national dialogue. But a weak central government -- combined with militias split along regional, tribal and ideological lines -- has added to the challenge.

The U.S. State Department said this past weekend it was concerned the fighting could lead to widespread conflict and backed the new government.

"We affirm our support for Libya's democratic transition and urge the seating of the new Council of Representatives as soon as possible," the statement added. "Finally, we stress the vital role Libya's Constitution Drafting Assembly plays in building the new country for which Libyans sacrificed so much during the revolution."