WASHINGTON (Reuters) - The second U.S. soldier killed in Afghanistan over the past week was named on Friday as Sergeant First Class Christopher Andrew Celiz of Summerville, South Carolina, the Department of Defense said.

Celiz, 32, was on his seventh deployment when he died in eastern Afghanistan on Thursday after being wounded by enemy small arms fire, the U.S. Army Special Operations Command said in a statement. The incident is under investigation.

He was treated immediately and evacuated to the closest medical facility, where he died of his wounds, the statement said.

Celiz was posthumously awarded the Meritorious Service Medal, Bronze Star Medal and the Purple Heart, it said.

“Chris was a national treasure who led his (Army) Rangers with passion, competence, and an infectiously positive attitude no matter the situation. He will be greatly missed,” said Lieutenant Colonel Sean McGee, commander of Celiz’s battalion.

A member of the Afghan security forces was also killed and several were wounded during Thursday’s combat, the Pentagon has said.

Four service members have died in Afghanistan since the start of the year, a Pentagon spokesman said. Eight soldiers died there between January and July 2017, according to the Pentagon.

Less than a week ago, U.S. Army Corporal Joseph Maciel, 20, of South Gate, California, was killed on July 7 in an apparent “insider” attack by a member of local security forces, and two other service members were wounded, the DOD said.

The United States is preparing a review of strategy in Afghanistan to examine issues, including U.S. troop presence and the prospect of negotiations with the Taliban, officials told Reuters.

The White House has not yet formally ordered the review, but current and former U.S. officials said they were preparing for a government-wide appraisal in the coming months. The White House asked for a similar review after President Barack Obama unveiled an Afghanistan strategy in 2009.

American-led forces invaded Afghanistan in 2001 to overthrow the Taliban government for harboring al-Qaeda militants. Since then, nearly 1,900 U.S. troops have been killed in the war.

President Donald Trump has opposed remaining in Washington’s longest war, but his advisers convinced him that the U.S. should stay. Last year, he authorized the deployment of 3,000 more troops, bringing the total to about 15,000.

Meanwhile, Afghan forces’ capability remains murky, and a U.S. government watchdog recently reported that the Afghan government controlled or influenced only about 56 percent of the country.