KABUL (Reuters) - Taliban fighters have stepped up pressure on Afghan forces in the western province of Badghis, killing 20 soldiers and capturing 20, an official said on Tuesday, as the militants make advances even as they hold peace talks with U.S. officials.

A large number of Taliban insurgents launched attacks on several army posts in the province’s Bala Murghab district, beginning on Saturday night, said Qais Mangal, spokesman for the defense ministry in Kabul.

“The fighting is still on,” Mangal said, adding that the Taliban had overrun four posts and government reinforcement backed by air support had been sent to prevent the whole area from falling to the insurgents.

A member of the Badghis provincial council, Abdul Aziz Beg, said 20 soldiers had been killed, 10 wounded and 20 captured by the hardline Islamist group.

The Taliban claimed responsibility for the attacks in Badghis, which is on the border with Turkmenistan.

Taliban spokesman Qari Yousuf Ahmadi said 20 soldiers had been killed, 28 captured and a large supply of weapons and ammunition seized.

The Taliban, ousted in 2001, say they are fighting to expel foreign troops, topple the Western-backed Afghan government and restore their version of Islamic law.

Talks with U.S. officials to end the war continued on Tuesday in Qatar, with the focus on the withdrawal of foreign troops, a guarantee Afghanistan will not be used as a springboard for militant attacks and a ceasefire.

The Taliban have refused to talk to Afghan government officials, labeling them a puppet of the United States.

Southeast of the Afghan capital, Kabul, in Ghazni city, an air strike on a vehicle killed seven Taliban on Tuesday, including a commander, said Mohammad Arif Noori, spokesman for Ghazni’s provincial governor. He said the strike happened close to a mosque and may have left civilian casualties.

Dr. Zaher Shah Nekmal, health director for Ghazni province, said he had received a report of 16 dead but had not yet received the bodies.

In a statement, the Taliban said one air strike hit a minibus and a second followed quickly, killing a total of 12 people and wounding six.

A NATO spokesperson could not be immediately reached for comment.

As many as 200 people were accompanying tractors that pulled a number of bodies on trailers to the provincial governor’s compound, said Waris Naimi, a spokesman for the Ghazni police, adding that police were trying to block the protest.

As the snow begins to melt, Taliban and Afghan security forces have stepped up attacks on each other but the extent of government losses is a major concern.

In January, President Ashraf Ghani, speaking at the World Economic Forum in Davos, Switzerland, said 45,000 members of the security forces had been killed since he took office in September 2014.

Some 14,000 U.S. troops are based in Afghanistan as part of a U.S.-led NATO mission to train, assist and advise Afghan forces. Some U.S. forces also carry out counter-terrorism operations.