TRIPOLI, Libya (CNN) -

Rival Libyan militias battled for Tripoli International Airport on Sunday, leaving nine people dead and 25 others wounded, the government said.

Shelling was threatening civilians as violence stretched along the airport road, which is dotted with residential neighborhoods. All flights in and out of the airport have been suspended.

CNN personnel could hear gunfire and blasts throughout the day. Heavy smoke billowed above the airport.

While the government issued a statement calling for calm, Libya's government is weak and militias outnumber and outgun its security forces. Many of these 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.

State-run al-Rasmiya television gave the death toll, citing Libya's Health Ministry.

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.

"The revolutionary brigades are inside Tripoli International Airport," the Libyan Revolutionaries Operations Room, an Islamist militia in the capital, posted on its Facebook page.

"The revolutionary forces have reached the perimeter of Tripoli International Airport ... clashes with some of the armed groups present there," the group said.

State-owned Afriqiyah Airways said on its official Facebook page that it was diverting some of its international arrivals to the city of Misrata, and that the airport in Tripoli would be closed until July 17.

Late Sunday morning, the sounds of fighting could also be heard in the vicinity of a Zintan base in a western suburb of Tripoli.

Libya's interim government released a statement Sunday that said regional brigades and "field commanders" are carrying out "operations," and they moved on Tripoli Airport with "no order or legitimate cover, coming from different directions ..."

The government is in talks with what the statement called the international community so that lives and "vital installations" are protected. Stop "these acts of war," the statement implored.

A state of emergency in all hospitals and clinics was issued.

Hugh Robertson, the United Kingdom's minister for the Middle East, urges an immediate end to violence at Tripoli International Airport.

Robertson said the violence was "putting the lives of people in the area in grave danger.

"We urge all sides to cease violence immediately and to engage in meaningful dialogue," he said.

In a statement the night before the fighting erupted, the U.S. State Department expressed concern about what it said was the "ongoing violence in Libya and dangerous posturing that could lead to widespread conflict there."

The U.S. renewed its calls for national dialogue in Libya.