U.S. Defense Secretary Jim Mattis has arrived in Afghanistan, making an unannounced visit to assess the needs in the war against Taliban and other militants.
Mattis, who is the first member of President Donald Trump's cabinet to visit Afghanistan, was expected to meet Afghan officials and U.S. troops while in Kabul.
His arrival coincided with an announcement that the Afghan defense minister and army chief of staff had resigned in the wake of a Taliban attack on an army base on April 21 that killed scores of soldiers.
Afghanistan is the sixth stop on a weeklong tour Mattis said was intended to bolster relations with allies and partners. He also visited Qatar, Saudi Arabia, Egypt, Israel, and the small East African country of Djibouti.
General John Nicholson, the top U.S. commander in Kabul, recently told Congress that he needed a few thousand more troops to keep Afghan security forces on track to eventually handling the Taliban insurgency on their own.
Mattis was due to meet top officials including President Ashraf Ghani less than two weeks after the U.S. military dropped its most powerful nonnuclear bomb, the MOAB, on Islamic State hideouts in eastern Afghanistan.
Mattis, who served in Afghanistan, has said he is compiling an assessment for Trump on Afghanistan's long-running conflict. He is the second senior U.S. security official to visit Afghanistan this month, after national security adviser General H.R. McMaster.
Around the time Mattis arrived, Ghani's office announced that he had accepted the resignations of Defense Minister Abdullah Habibi and the army chief of staff.
Their departure followed one of the deadliest Taliban attacks targeting the Afghan security forces, an assault on an army base in the northern city of Mazar-e Sharif.
The Defense Ministry said that more than 100 military personnel were killed or injured in the attack, but officials in Kabul told RFE/RL that more than 130 had been killed. Some officials put the toll even higher.
Ghani's office also said he had replaced the commanders of four army corps in response to the attack.
Trump's administration is seeking to build its strategy for the Afghan conflict -- the longest war in U.S. history.
Taliban militants hold large amounts of territory more than 15 years after being driven from power by a U.S.-led invasion following the September 11, 2001, terror attacks on the United States.
General Nicholson recently told a congressional hearing that he needed several thousand more international troops in order to break a stalemate in the war against the Taliban.
U.S. officials say that Nicholson's request was advancing through the chain of command.