An Army vet who served two tours in Afghanistan has been deported to Mexico because of a 2008 drug-trafficking conviction.
U.S.sanctions against Russian arms manufacturers have made servicing Mi-17 helicopters increasingly difficult.
Afghan security forces have identified key areas of the country that must be secure for elections later this year.
Gen. Joseph Dunford, chairman of the Joint Chiefs of Staff, said he wants to understand the goals for the coming months.
The Afghan capital is now the main focus of the anti-Taliban fight, with U.S. special forces conducting raids.
Afghanistan's President Ashraf Ghani has put a peace offer on the table, and analysts say the ball is in the Taliban's court.
Critics say a new Defense Department inspector general report didn't delve deep enough or try to right past wrongs.
U.S. Defense Secretary Jim Mattis said Tuesday he believes victory in Afghanistan is still possible.
Last month, 800 more U.S. soldiers arrived in Afghanistan, bringing the total to nearly 15,000 troops.
The Khorasan Province, an ISIS affiliate in Afghanistan, claimed responsibility for the Kabul bombing.