The sight of a deadly explosive firing past them appears to have become so normal that these men laugh and joke while the rockets light up the sky. Many of the men are volunteers and former rebels who fought in the uprising that toppled Muammar Gaddafi five years ago.

The government-backed forces began their offensive to take back Sirte in May this year. The city is the so-called Islamic State biggest stronghold in Libya and has been under the terror group's control since February 2015.

U.S. air strikes are easing the passage of Libyan forces, a senior field commander said on Wednesday.
Video shows An AV-8B Harrier jet took off from the USS Wasp assault ship in the Mediterranean Sea on Monday, as it prepared to conduct strike missions against Islamic State group targets in Libya.

The US is bombing targets in and around the Libyan city of Sirte, in a notable expansion of the US-led coalition's military mission against IS.

In some part of the clip the U.S. Defense Department released video Thursday (August 4) showing U.S. warplanes taking off from the flight deck of the USS Wasp from the Mediterreanean Sea headed for Sirte.

Forces allied with Libyan Prime Minster Fayez Seraj have been battling Islamic State in Sirte - the home town of former dictator Muammar Gaddafi - since May.

The militants seized the Mediterranean coastal city last year, making it their most important base outside Syria and Iraq. But they are now besieged in a few square kilometres of the centre, where they hold strategic sites, including the Ouagadougou conference hall, the central hospital and the university.

The air strikes on Monday - which were authorised by U.S. President Barack Obama hit an ISIL tank and two vehicles that posed a threat to forces aligned with Libya's GNA.

This was the third US airstrike against ISIS in Libya. But U.S. officials said this one marked the start of a sustained air campaign rather than another isolated strike.

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