Cracks may be emerging in the so-called ironclad military alliance between South Korea and the U.S., stoking worries in Seoul that the Trump administration is looking at withdrawing troops from the peninsula.

Defense Secretary Mark Esper isn’t ruling out reductions to U.S. Forces Korea, telling a forum Tuesday that, while no order has been given, the administration was looking to adjust its posture globally. He was responding to a July 17 report in the Wall Street Journal saying that the Pentagon had given President Donald Trump options to draw down troops amid a deadlock over the U.S.’s demands for more funding.

While Trump has complained about open-ended U.S. military commitments since before taking office, the threat of a withdrawal has increased since his decision last month to reduce the country’s military footprint in Germany. South Korean President Moon Jae-in’s government has said little about a troop cut if the two sides can’t renew their expired Special Measures Agreement, but some worry the discussion could signal weakness to neighboring North Korea and China.