KABUL (Reuters) - Afghan security forces backed by U.S. air strikes have retaken a southern district from the Taliban as part of a drive to weaken the insurgents’ hold on Helmand province and push them back from around its capital, Lashkar Gah, officials said on Monday.

A two-day offensive, supported by numerous air strikes from U.S. F-16 fighters and Apache helicopters, launched on Saturday saw security forces take the district center of Nawa, to the south of Lashkar Gah, officials said.

More than 50 fighters were killed and vehicles and equipment were destroyed, said defense ministry spokesman General Dawlat Waziri. Over 100 improvised explosive devices were also disabled, Task Force Southwest, the U.S. Marine Corps-led training and assistance mission in Helmand said in a statement.

The operation, which comes as the United States weighs sending more troops to Afghanistan, will continue with security forces moving further south along the main road to the town of Garmsir, officials said.

The recapture of Nawa district, which lifted a serious threat to transport links into Lashkar Gah, reflects renewed focus by Afghan forces and their U.S. advisers on Helmand, an insurgent heartland that is source of much of the world’s illegal opium.

“Nawa is a major north-south route for transportation, so as people travel north, they would typically travel through Nawa. From that perspective it’s a very significant geographic location,” said Col. David Gibbs, the Task Force Southwest officer in charge of police training and assistance.

The operation also removed a threat to civilian aircraft landing in Bost Airfield, just outside Lashkar Gah.

The Taliban, fighting to re-establish strict Islamic rule in Afghanistan and drive out international forces backing the government in Kabul, control large stretches of the province and have targeted Lashkar Gah.

It was not possible to independently verify the defense ministry’s casualty figure and no comment on insurgent losses was immediately available from the Taliban.