WASHINGTON (AP) — The United States has declined to join other countries in criticizing China over allegations of torture against human rights lawyers.

The U.K., Germany, Canada and eight others signed a letter raising concerns about lawyers and rights activists detained incommunicado for long periods. The letter urges China to investigate torture claims against lawyer Xie Yang and others.

The U.S. abstention comes as activists raise growing concerns that the Trump administration is de-emphasizing human rights in diplomacy. Secretary of State Rex Tillerson struck a conciliatory tone with China during a visit last week.

The State Department won’t say why the U.S. didn’t sign, who made the decision and whether the White House was involved. The State Department says the U.S. raises “serious” human rights concerns as part of “regular discussions” with China.