LONDON (Reuters) - NATO is assessing a request from the alliance’s military authorities to send more troops to Afghanistan and will make a decision on the scale and scope of the mission within weeks, Secretary General Jens Stoltenberg said on Wednesday.

The request for what Stoltenberg said was “about a few thousand” more troops reflects the West’s alarm about the worsening security situation in Afghanistan, territorial gains by Taliban militants and military and civilian casualties.

“We are now assessing that request. We will make decisions on the scale and scope of the mission within weeks but this is not about returning back to a combat operation in Afghanistan,” he said after meeting British Prime Minister Theresa May.

Reuters reported in late April that U.S. President Donald Trump’s administration was weighing sending between 3,000 and 5,000 U.S. and coalition troops to Afghanistan.

NATO already has some 13,450 troops in Afghanistan, including about 6,900 U.S. military personnel, who are training the Afghan armed forces to eventually take over the country’s defense and security.

In addition, the United States has about 1,500 more troops in a parallel mission, part of a counter-terrorism unit that mostly targets pockets of al Qaeda and Islamic State fighters.

Stoltenberg stressed that any new NATO arrivals would not be in a combat role. “It will continue to be a train, assist and advise operation,” he said of the so-called Resolute Support mission that was launched in January 2015 and signaled the end of an official combat role for NATO troops in Afghanistan.

A decision could be taken by NATO defense ministers in June, according to an alliance official. The NATO leaders summit in Brussels on May 25 was probably too soon, the official said.

Almost 16 years since the United States tried to topple Afghanistan’s Taliban, who had harbored al Qaeda militants behind attacks on New York and Washington, the West remains entangled in an effort to stabilize a country facing resurgent rebels.

NATO Secretary General Jens Stoltenberg gestures during a meeting at the European Parliament in Brussels, Belgium May 3, 2017. REUTERS/Eric Vidal

Facing public fatigue at the long-running conflict, the North Atlantic Treaty Organisation has sought to progressively reduce its presence in the country by building up the country’s armed forces, notably creating an Afghan air force.

However, loss of territory to Taliban and Islamic militants, a rise in civilian casualties and a fall in the number of Afghan security forces have led the U.S. administration under Trump to review Afghanistan policy.

Over the past 18 months, Taliban insurgents have twice succeeded in seizing the northern town center of Kunduz for brief periods and the latest fighting underscores the challenge Afghan forces face to quell the insurgency.

According to the United Nations, 583,000 people fled their homes due to conflict in 2016, the highest number of displacements since records began in 2008.

U.S. National Security Advisor H.R. McMaster visited Kabul in April to assess the situation, days after the U.S. military dropped one of the largest conventional weapons ever used in combat during an operation against Islamic State militants in eastern Afghanistan.

“I strongly believe that the best answer we have to terrorism, the best weapon against terrorism, is to train local forces to fight terrorism, to stabilize their own country,” Stoltenberg said.

NOT ENOUGH?

Any increase of several thousand troops would leave U.S. forces in Afghanistan well below their peak of more than 100,000 troops in 2011, when Washington was under huge domestic political pressure to draw down the costly operation.

Some U.S. officials told Reuters they questioned the benefit of sending more troops to Afghanistan because any politically palatable number would not be enough to turn the tide, much less create stability and security. To date, more than 2,300 Americans have been killed and over 17,000 wounded.

For now, deliberations include giving more authorities to forces on the ground. This could allow U.S. advisers to work with Afghan troops below the corps level, potentially putting them closer to fighting, a U.S. official said.

Stoltenberg said NATO trainers could also do more.

“We are now looking into requests regarding some areas like more education, for the military academies, but also training special operation forces and air forces,” he said.