Libyan forces loyal to a former military commander have intensified their airstrikes on Tripoli, where heavy fighting and blocked roads have left civilians trapped in their homes, officials said Monday.

Gen. Khalifa Haftar's self-styled Libyan National Army launched an operation to retake the capital on April 4 and has been locked in heavy fighting in and around the city with militias loosely allied with a U.N.-supported government. The clashes have killed more than 270 people, including 21 civilians, according to the latest U.N. figures released last week.

Libyan officials said LNA airstrikes have targeted the Nawasi Brigade in the Abu Salim district, about 7 kilometers (4 miles) from Tripoli's center. At least four civilians were killed, they said.

Haftar's push on Tripoli in Libya's northwest is the latest turn in a cycle of factional violence and chaos dating back to the ouster of former President Moammar Gadhafi in 2011 and NATO's aerial operations. Libya has remained dogged by turmoil since 2011 when a NATO-backed uprising led to the ouster and death of Gadhafi after more than four decades in power. Since then, Libya's stark political divisions have yielded two rival seats of power, one in Tobruk and another in Tripoli, and a host of heavily armed militia groups. Haftar is not recognized by the international community, as the elected parliament of the country is centered in Tripoli. However, Haftar, with financial and political support from certain countries, including some Gulf states, is an influential actor in the war-torn country.