Afghan security forces have driven the Taliban out of a key district in southern Helmand province from where they had been threatening the provincial capital of Lashkar Gah, Afghanistan's Defense Ministry Spokesman Daulat Waziri said Monday.

Waziri said that the battle to recapture the district of Naway had been fierce. He added that more than 50 Taliban fighters were killed and five soldiers were wounded.

Government troops also captured a large cache of ammunition and guns.

Naway is located just 16 kilometres from Lashkar Gah, and had been a staging arena for militant attacks on the city.

The Taliban did not immediately comment on reports of the district's fall.

US and Nato troops are in Helmand to assist Afghan security forces when needed.

Civilian deaths in militant bombings have increased: UN report

A record number of 1,141 civilians were killed by insurgent bombings in Afghanistan, a UN report said Monday.

According to the report, the number of deaths have increased by 12 per cent over the same period last year. It also said that 2,348 people have been injured in the attacks.

UN High Commissioner for Human Rights, Zeid Ra'ad Al Hussein, said the that “horrifying” figure of 1,662 people killed between January and June of this year “can never fully convey the sheer human suffering of the people of Afghanistan".

“Each one of these casualty figures reflects a broken family, unimaginable trauma and suffering and the brutal violation of people's human rights,” he added.

The report confirmed that a massive truck bomb in the centre of Kabul on May 31, which killed at least 90 people, was the deadliest attack since the US-led invasion that toppled the Taliban in 2001. It also noted that more women and children were among the dead this year.

Commending Afghanistan's security forces, the report said that the number of civilians caught in the ceasefire has decreased as compared to last year. It said 434 civilians were killed during military operations against insurgents.

General Dowlat Waziri blamed the high toll on the insurgents' use of human shields.

“The army is being very careful during operations to prevent civilian deaths,” Waziri told The Associated Press.

Taliban spokesman Zabihullah Mujahid rejected the “biased” report, saying it did not take into account civilians killed by Afghan and coalition forces in areas controlled by the Taliban. He did not provide any figures and there was no way to verify his claims.

The insurgents have expanded their footprint in Afghanistan since US and Nato forces formally concluded their combat mission at the end of 2014, and the Taliban now control a number of districts across the country.

Elsewhere in Afghanistan, the Taliban snatched three border police officers from their car in the western Herat province, including a woman, and killed them, said Jelani Farhad, the provincial governor's spokesman.