The Donald Trump administration faces growing pressure from US lawmakers to freeze the sale of F-35 jets to Turkey as the NATO ally holds an American pastor in jail and pushes to acquire Russian military equipment.

The Senate Armed Services Committee this week advanced must-pass annual defense legislation that calls on the administration to remove Turkey from the fifth-generation fighter program over its detention of Andrew Brunson. The equivalent House bill, meanwhile, would hold up major arms sales to Turkey until the administration submits a report on the state of US-Turkish military and diplomatic relations amid Turkish efforts to buy the Russian S-400 air defense system.

The Senate bill, which has not yet been made public, also calls on the administration to sanction Turkey if it purchases the S-400. Last month, Turkey said it would move up the delivery of the $2.5 billion system to July 2019.

Some lawmakers are also pressing the administration to block the F-35 sale under last year’s Countering America’s Adversaries Through Sanctions Act, or CAATSA, which targets entities that do business with sanctioned arms firms. The Barack Obama administration first sanctioned S-400 maker Almaz-Antey in 2014 for its alleged role in Russian interference in Ukraine.