BAGRAM AIRFIELD, Afghanistan (Reuters) - One U.S. soldier was killed and around 20 U.S. and Afghan troops were wounded during a push against Islamic State fighters in Afghanistan, officials said on Thursday, as Washington wrestled with a months-long debate about the 16-year-old war.

The incident late on Wednesday in Nangarhar province came as several Pentagon officials visited Afghanistan, including Air Force Secretary Heather Wilson and the top generals of the Army and Air Force.

As the sun pounded down on Bagram Airfield, Wilson, the generals and scores of U.S. troops joined a solemn ceremony to mark the moment the flag-draped coffin carrying the fallen soldier was loaded onto a flight back toward the United States. Some of the troops quietly wept.

Few details about the blast were available, including a firm number of U.S. wounded or the name of the soldier who was killed. One U.S. official said most of the injured American troops had already been released from medical care.

Two officials said the U.S. and Afghan forces were hit by an explosion inside a building in Nangarhar. They did not say what caused the explosion.

For Wilson, a former congresswoman who took over the Air Force’s top civilian job three months ago, the ceremony was an unexpected part of her reintroduction to the Afghan war.

With the latest death, 10 U.S. troops have been killed in Afghanistan this year, according to the U.S. military. Nearly 2,400 American troops have been killed since the war began in response to al Qaeda’s Sept. 11, 2001, attacks in the United States.

The incident was a reminder of the high stakes as U.S. President Donald Trump considers requests from the top commander in Afghanistan for thousands more troops beyond the roughly 8,400 who are already here.

The goal would be to help Afghan forces break a stalemate against Taliban insurgents and, at the same time, prevent rival Islamic State fighters from expanding here as their territory shrinks in Syria and Iraq.

U.S. intelligence agencies have assessed that conditions in Afghanistan will almost certainly deteriorate through next year, even with a modest increase in military assistance from America and its allies.

Trump, Vice President Mike Pence and his national security team are scheduled to discuss Afghan war strategy and regional policy guiding it at a meeting at Camp David on Friday.

Wilson and Air Force Chief of Staff General David Goldfein declined to wade into the policy debate about Afghanistan. But, Wilson said, “Nothing has changed or is likely to change with respect to America’s determination to go after terrorists wherever they may be.”