TRIPOLI, May 18 -- The militant group led by the retired General Khalifa Haftar made an assault on Libya's parliament on Sunday afternoon, according to his spokesman.

The gunmen wore plain clothes and fired on congress building, and later some of them dashed inside to expel the lawmakers, forcing a session to adjourn, according to one interior ministry official.

He said the Battalion 127 was in charge of guarding the parliament and fired back at the gunmen.

Some kilometers away, sound of anti-aircraft guns and light weapons could be heard. Local TV footage showed a parliamentary session was forced to stop.

Witnesses said armed clashes also took place on roads leading to Tripoli airport. Some saw vehicles equipped with guns rushing towards downtown and heavy smoke rose from the parliament building.

Meanwhile, retired General Khalifa Haftar's spokesman made a statement saying their fighters launched an attack on the parliament to purge the Islamists. The spokesman added their assault met with resistance.

Haftar led his self-proclaimed "national army" into Libya's second largest city Benghazi at dawn on Friday, shelling many Islamism militant bases, including Ansar Al-Sharia's and February 17 Brigade's compound, leaving at least 79 people dead and about 140 wounded.

He claimed his maneuvers were to purge the city from" terrorists," but the interim government defined it as a "coup" and asked him to exercise self-control and "resist any temptation to intrude."

On Saturday the Libyan interim government set up a no-fly zone in an attempt to restrain Haftar's air forces after he threatened to launch more air strikes.