A US service member was killed in action in Afghanistan on Monday, the US military said in a statement.
It gave no further details and withheld the name of the service member until the next of kin were informed.
More than a dozen foreign force members have been killed in Afghanistan in 2019.
No militant group immediately claimed responsibility for any attack on US forces.
About 20,000 foreign troops, most of them American, are in Afghanistan as part of a US-led NATO mission to train, assist and advise Afghan forces. Some US forces carry out counter-terrorism operations against Islamist militant groups.
The United States has been in negotiations with Taliban militants over the past year on a deal under which the United States could withdraw its forces from its longest war in exchange for Taliban security guarantees.
This month, US negotiators said they would take a break from the talks after the insurgents launched a suicide attack on a large US base.
The Taliban control more territory than at any point since they were ousted from power in 2001.
