BRUSSELS (Reuters) - NATO is set to agree on Thursday to increase its Afghanistan training mission by some 3,000 troops, alliance officials said, after the United States switched tack in long-running efforts to defeat Taliban militants and end the conflict.

Fresh NATO personnel will not have a combat role but the alliance hopes more soldiers can train the Afghan army and air force to complement U.S. President Donald Trump’s strategy to send more American counter-terrorism troops to the country.

“We have decided to increase the number of troops ... to help the Afghans break the stalemate, to send a message to the Taliban, to the insurgents that they will not win on the battleground,” NATO Secretary-General Jens Stoltenberg told a news conference on Tuesday.

NATO defense ministers are expected to approve the deployment in the latter part of a two-day meeting that starts on Wednesday.

The troops would be deployed from the start of 2018, a NATO official said.

The West says it is determined to stabilize a country facing resurgent rebels 16 years after the United States sought to topple the Taliban rulers who had harbored the al Qaeda militants behind attacks on New York and Washington.

Stoltenberg said an attack on Tuesday on a television station in Kabul underlined the importance of fighting militants and supporting Afghan security forces. Islamic State claimed responsibility for the assault, without giving evidence.

Trump’s envoy to NATO, Ambassador Kay Bailey Hutchinson, said the U.S. goal was to show Taliban militants they could not win in military combat.

Trump’s strategy in Afghanistan, unveiled in August, rests on providing more troops, a stronger Afghan army, support from regional allies such as India and a harder line with Pakistan.

NATO Secretary-General Jens Stoltenberg speaks during an interview in Kabul, Afghanistan September 27, 2017. REUTERS/Mohammad Ismail

U.S. officials say Pakistan provides refuge and support to the Taliban and other extremist groups, which Pakistan denies.

“We’d like to see Pakistan come in, in a positive effort to help stabilize Afghanistan,” Hutchinson said.

There have been several attempts in recent years to broker a settlement between the Western-backed government in Kabul and the Taliban, but all have failed. Without the militants at the table, experts say it is hard to envisage a peace settlement.

NATO allies have already promised almost $3 billion to help the United States fund the Afghan military until 2020, which is developing an air force to complement its ground forces.

Troop contributions had rested on NATO allies seeing more details about Trump’s strategy, diplomats said.

NUMBERS GAME

The NATO contribution would boost the training mission, called Resolute Support, to around 16,000 troops, Stoltenberg said. About half the additional troops would come from the United States and the rest from NATO allies and partner countries.

U.S. Army General John Nicholson, the commander of the Resolute Support mission and of U.S. forces in Afghanistan, said in February that a few thousand more troops would make a difference.

About 11,000 U.S. troops are serving in Afghanistan, the Pentagon said in August, including almost 7,000 in Resolute Support, according to NATO data.

Under Trump’s new strategy, U.S. Defense Secretary Jim Mattis said in September that more than 3,000 additional U.S. troops would be deployed to Afghanistan.

Taken together, the new deployments could take the total number of Western troops in the country to above 20,000, according to current and projected troop numbers -- well below a 2011 peak of more than 100,000.