U.S. national security adviser H.R. McMaster was in Kabul on Sunday for what is the first visit by a Trump administration official to Afghanistan, officials here said, coming just days after U.S. forces dropped a 22,000-pound bomb on militants there and revived debate over the war.

President Trump has said little about the conflict in Afghanistan, spurring concerns among Afghan officials about his administration’s commitment to the fight.

More than 8,000 U.S. troops are helping Afghan forces battle the Taliban. The commander of U.S. forces in Afghanistan, Gen. John W. Nicholson Jr., has said that he will need thousands of additional troops to better support the international coalition’s mission.

On Friday, U.S. forces used the largest conventional bomb in the military’s arsenal — the GBU-43 — to hit a stronghold of Islamic State militants in eastern ­Afghanistan.

The deployment of such massive weaponry stunned many in Afghanistan and around the world, jolting the public’s ­attention back to what has been a grinding war that began in 2001. The U.S. military has not released its assessment of the bomb’s impact, but officials here say that more than 90 militants were killed.

National security adviser H.R. McMaster. (Susan Walsh/AP)

Senior U.S. officials said last week that a review of the Afghanistan strategy is underway.

The officials, who spoke in a background briefing during a White House visit by the secretary general of the North Atlantic Treaty Organization, said there is no specific deadline for the policy review.

“It’s based on when the president makes a decision,” one senior administration official said.

While here, McMaster, who served in Afghanistan for two years, met with Nicholson, senior Afghan officials and other NATO commanders overseeing the mission to advise Afghan security forces.

“The leaders discussed regional dynamics and joint efforts to counter terrorist groups, including al-Qaeda and ISIS,” the U.S. Embassy in Kabul said in a statement, using an alternative acronym for the Islamic State.

McMaster also encouraged the government to intensify its reform efforts “to strengthen governance in Afghanistan,” the embassy said. The office of the Afghan chief executive, Abdullah Abdullah, said McMaster praised the government as “one of the most reliable allies of the United States,” and the Afghan Defense Ministry said the visit marked a “new phase of friendship and cooperation” between the two countries.

But perhaps the most important task for McMaster is evaluating the progress in the fight against the Taliban insurgency. Taliban militants control more territory than at any other time since 2001, when U.S. troops helped to overthrow the Islamist ­regime.

The United States has spent about $117 billion on reconstruction in Afghanistan, including $70 billion to support its security forces, according to the Special Inspector General for Afghanistan Reconstruction, a U.S. government oversight commission. Despite that, desertion rates and civilian casualties are on the rise — and Afghan security forces continue to lose ground.

“I have always said that it is better to equip Afghan forces. If we are not equipped better, the situation will not improve,” said Sayed Malik Maluk, an official in the policy department of the Afghan Defense Ministry.

Officials here said the government would raise its request for more military aid with McMaster, who is seen as an ally of those pushing for the Trump administration to send more troops. Defense Secretary Jim Mattis is expected to make a formal recommendation on troop numbers to the president. But it is unclear how McMaster’s suggestions will fit into that review.

“I have said this repeatedly to foreign commanders,” said Maluk, who also served as a corps commander in the volatile Helmand province in the south from 2008 to 2015. “We need better and more modern gear, especially for the air force.”

McMaster has been critical of deploying small numbers of troops to fight wars, instead advocating for a more comprehensive approach, including the use of development funds and diplomacy. These prescriptions would appear to run counter to the views of the Trump administration, which has scoffed at diplomacy and proposed gutting foreign aid.

In Afghanistan, McMaster has said that the U.S. reliance on militias ended up undermining the government. When serving here from 2010 to 2012, McMaster oversaw the Combined Joint ­Inter-Agency Task Force Shafafiyat (Transparency), which had a mandate to clean up corruption within the contract system used by the international military ­forces.

In 2015, he summed up what he saw as one of the key problems.

“There was a connection with a criminal underworld and a ­political upperworld and a ­political settlement that rested in large measure on criminality and impunity,” he told an anti­corruption group, Transparency International.

“McMaster is a strategic thinker and a good friend of Afghan­istan,” said Rahmatullah Nabil, former chief of the National ­Directorate of Security, Afghan­istan’s spy agency. He has “great knowledge of Afghanistan’s problems, including corruption and war.”

“If we only decide to support Afghan troops, it won’t work,” Nabil said. “We also need to focus on political stability.”

Sayed Salahuddin and Walid Sharif contributed to this report.