Missiles were fired at Libya's capital Tripoli, including the city's only functioning airport, forcing authorities to divert flights to anther airport to the south, government and airport officials said Wednesday, less than a week after the UN brokered a cease-fire between rival armed groups.The source of Tuesday's missile attack was unclear and there were no casualties reported, the officials said. They spoke on condition of anonymity because they were not authorized to brief media.Mitiga International Airport posted on its Facebook page late Tuesday that the airport was closed and all flights were being diverted to Misrata International Airport.Pilots were called Tuesday night to fly planes out of Tripoli to Misrata so they would not be hit, said one official."This was the only option to make sure they were not destroyed after the missiles landed on the airport grounds," he said.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and FacebookThe missile attack followed recent fighting in Tripoli between rival armed groups, which left at least 61 people dead. A cease-fire has been in place since last week.Clashes in Tripoli erupted Aug. 26 when militias from Tarhouna, a town south of Tripoli, attacked southern neighborhoods of the capital, prompting militias supporting the U.N.-backed government in Tripoli to come to the city's defense. The fighting killed 66 people and wounded 187.Separately, the extremist Islamic State group on Tuesday claimed responsibility for an attack on the headquarters of Libya's national oil company in the capital Tripoli that killed two people and wounded at least 10 others.Islamic extremists expanded their reach in Libya after the 2011 uprising plunged the country into chaos and toppled and later killed longtime ruler Muammar Gaddafi.IS was driven from its main stronghold, the coastal city of Sirte, in 2016 and fled inland.Libya is currently split between rival governments in the east and the west, each backed by an array of militias.