KABUL - US aircraft carried out a dozen strikes in Helmand province in southern Afghanistan on Wednesday as fierce battles continued with Taliban insurgents around the town of Marjah near the provincial capital, a US army spokesman said.

The strikes came a day after one US service member was killed and two other Americans and a number of Afghan special forces soldiers were wounded during operations in the province, which has seen months of heavy fighting.

US army spokesman Col. Michael Lawhorn said US special forces were still in place on Wednesday, supporting Afghan army units in Marjah and Sangin district, further to the north, and air support had also been provided. “US forces have conducted 12 air strikes in support of operations in and around Marjah,” he said.

The strikes highlight the intensity of the combat in Helmand, a traditional Taliban stronghold where hundreds of British and American soldiers and marines were killed or wounded fighting the insurgency. Provincial police chief Abdul Rahman Sarjang said 120 Taliban insurgents had been killed since Monday, when security forces began an operation to clear Marjah. There was no independent confirmation of the figure.

“We have had a lot of achievements from this operation and we will continue until we free Marjah from Taliban,” he said. The U.S. and Britain have sent additional special forces personnel to the province to help train and assist Afghan police and army units. But officials said their main role is not to be involved in fighting. Over the past six months, the Taliban has overrun much of the province, one of the world’s major centres of opium production, in a broad offensive that has put Afghan government forces under severe strain.

Although international troops ended combat operations last year, the United States has continued to conduct some air strikes in support of Afghan troops, while special forces units have also been drawn into fighting on occasion, officials have said.

The fact that US troops are back in Helmand and engaged in fighting, even after the end of the main combat mission, has raised questions about the effectiveness of Afghan forces, which have struggled to contain the insurgency. In Marjah, the road from the provincial capital Lashkar Gah has been repeatedly cut and blocked by landmines, complicating efforts to relieve government forces that have been restricted to a small area around the administrative centre. Heavy fighting went on all night on Tuesday and the Taliban said fighters had shot down a helicopter in Marjah. The claim was denied by the U.S. military which said a helicopter had suffered mechanical damage.

The Afghan Taliban have launched an unprecedented winter surge that points to a desire for an upper hand in peace talks, analysts say, while some suggest rogue elements may be bolstering the effort to derail overtures by Islamabad to India.

Taliban fighting normally quiets down in winter months with the insurgents resting ahead of an annual spring offensive, but this year has seen a series of fierce attacks - many focused on Kabul in recent weeks, including three in the capital since Friday.

Some say the ongoing fighting is a bid by Taliban leader Mullah Akhtar Mansour to consolidate his position ahead of four-way talks between Afghanistan, Pakistan, the US and China slated for next week, a precursor to a revived peace dialogue between Kabul and the insurgents.

Ahmed Rashid, a leading expert on the Afghan Taliban, said Mansour was tightening his grip on power through the high-profile attacks, after a shootout between rival insurgent commanders ‘in Pakistan’ in December left him wounded.

"We've never had such a winter offensive before from the Taliban. That winter is going to roll into a continuous spring-summer offensive," he told AFP.

"That is looking very dangerous. Mansour is consolidating his position. If he's seen as a military success they will remain loyal to him.

"Military success also de-legitimises the anti-Mansour faction that is emerging," he said, referring to the recent formation of a splinter group challenging his rule.

"The insurgents are trying to show to the world that they have presence in the country and get more concession in the peace talks," said Dawlat Waziri, a defence ministry spokesman. But Pakistan is also playing a role, regional analysts said.

"The Taliban do not have the authority to decide on peace talks, they are controlled by others," said Zalmay Wardak, a Kabul-based military analyst.