CAIRO (AP) — At least six people were killed and 25 injured Sunday when rival militias battled for the control of the international airport in Libya's capital. Civil aviation authorities announced the airport will be closed for three days because of security concerns. 
 
 Smoke rises on the horizon in Tripoli, Libya, early Sunday, July 13, 2014. Explosions and gunfire have been heard around the international airport in Libya's capital as airlines have canceled some international... (Associated Press) 
 
 Gunfire from the battles echoed through Tripoli as fierce fighting raged between Libyan forces and allied militias and a powerful militia from the western city of Zintan that controls the airport, a member of a revolutionary battalion attached to Libya's army chief of staff that took part in the battle said. 
 
 Those living in the vicinity said troops surrounded the airfield and fired rockets at buildings inside. Thick columns of black smoke rose overhead and could be seen from downtown Tripoli. 
 
 The health ministry said six people were killed in the fighting and 25 were wounded. 
 
 Authorities said Saturday that the airport was to have been handed over into government control. The government largely relies on the same militias to police the streets as its security forces remain in disarray. 
 
 The powerful Zintan militia had taken control of the airport, providing security for the strategic installation, following the fall of longtime dictator Moammar Gadhafi in 2011. 
 
 The militias, many of them organized to fight against Gadhafi troops, remained a powerful component in the post-war Libya, filling the void left by weak police and security and cooperating with the government to provide order. 
 
 But rivalries between militias for control and resources were also the cause for fierce fighting among them; and posed a constant challenge to the central government. 
 
 On Sunday, the country's civil aviation authority said the airport will be shut for three days pending the security situation, advising airlines to land at other airports in Libya. 
 
 Egypt's national carrier EgyptAir said it canceled two flights Sunday to Tripoli as hundreds of travelers remained inside the airport waiting for it to re-open. Both British Airways and Turkish Airlines also canceled flights Sunday. ||||| Heavy fighting between rival militias vying for control of Libya's main airport in Tripoli has left at least seven people dead and halted all flights. 
 
 Explosions and anti-aircraft gunfire were heard from early Sunday morning on the airport road and other parts of the capital until the situation seemed to calm down in the late afternoon. 
 
 The fighting was the worst in Tripoli since more than 40 people were killed in clashes between militias and armed residents in November. 
 
 Besides the seven fatalities, another 36 people were wounded in the clashes, the Libyan Health Ministry said. 
 
 Residents said that militia members from the northwestern region of Zintan who had controlled the airport came under fire, and local TV footage suggested that the attacking rebels were from the western city of Misrata. 
 
 The United Nations has said it has temporarily relocated some of its international staff out of Libya after heavy fighting broke out between rival militias vying for control of Libya's main airport. 
 
 "We can confirm a temporary relocation for security reasons," UN spokesman Farhan Haq said. 
 
 Zintan versus Misrata 
 
 Zintan forces, which have controlled the airport since Gaddafi's overthrow, and Misratis had been put on the state payroll in an unsuccessful attempt by the government to secure their cooperation and try to bolster the rule of law. 
 
 Comments on pro-Misrata websites suggested that the force was freeing the airport from Zintani control to hand it over to authorities. 
 
 The central government denounced the attackers as illegal. 
 
 "The operation is led by civil leaders belonging to brigades and troops ... moving without orders and legal cover," the government of Prime Minister Abdulllah al-Thinni said in a statement. 
 
 Local news channel Al Nabaa showed men in military vehicles with Misrata insignia opening fire with heavy weapons. 
 
 Heavy smoke could be seen rising above the airport as an official said: "All domestic and international flights have been halted." 
 
 Al Nabaa TV showed a Libyan Airlines jet and a transport aircraft engulfed in smoke while vehicles fired anti-aircraft volleys and fighters took up positions next to a field of sheep. 
 
 Social media websites said that several rockets had hit the airport perimeter. 
 
 Photographs on Facebook showed thick smoke at what was said to be the parking lot in front of the terminal. Families were trapped inside the building, local websites said. 
 
 The violence comes as the country awaits the results of the June 25 parliamentary elections. 
 
 Earlier the US warned that the conflict in Libya could be "widespread" following an acknowledgement by electoral officials that fraud had clouded the poll. 
 
 "The United States is deeply concerned by the ongoing violence in Libya and dangerous posturing that could lead to widespread conflict there," Jen Psaki, of the US state department, said on Saturday. 
 
 Officials and Libya's partners had hoped the vote would give a push to state building and ease political tensions. 
 
 Security concerns 
 
 Tripoli has seen a surge in kidnappings but has been mostly spared the kind of violence that has rocked the eastern city of Benghazi, where clashes between self-styled Islamist groups and forces loyal to a renegade general occur almost daily. 
 
 On Thursday, the UN Support Mission in Libya announced it was pulling out dozens of staff because of security concerns. 
 
 Libya, an OPEC member, is divided between rival militias from urban communities and tribes, as well as Islamist and more moderate forces. 
 
 Oil production has fallen to a fraction of the 1.4 million barrels a day that Libya produced before July 2013 when a wave of protests erupted at oilfields and ports. 
 
 The loss of oil revenues has caused a budget crisis as Libya depends on energy exports.
– All flights to Libya's main international airport have been suspended while rival militias battle for control of the facility. In Tripoli's worst violence since November, at least seven people have been killed and dozens injured in battles between militia members from the Zintan region, who have controlled the airport since the fall of Moammar Gadhafi, and fighters believed to be from the city of Misrata, Al Jazeera reports. Witnesses reported hearing explosions and anti-aircraft gunfire coming from the airport early yesterday. According to witnesses, Libyan troops fighting with the Misrata militia surrounded the airfield and fired rockets at buildings inside. Civilian aviation authorities say the airport will be closed for at least three days, the AP reports. The latest violence between the militias that fill many security functions in Libya comes as the country waits for the results of last month's elections, which the US fears could lead to more fighting. The US "is deeply concerned by the ongoing violence in Libya and dangerous posturing that could lead to widespread conflict there," a State Department spokeswoman said yesterday.