European lawmakers are putting Congress on notice that a bill to allow 9/11 victims to sue Saudi Arabia could inadvertently harm relations with some of America’s closest allies across the Atlantic.

The Dutch parliament wrote to House lawmakers ahead of a July 14 hearing to warn them that the Justice Against Sponsors of Terrorism Act (JASTA) would represent a “gross and unwarranted breach of Dutch sovereignty” that could result in “astronomical damages.” The July 12 letter obtained by Al-Monitor endorses the Obama administration’s opposition to the bill, and asks that Congress take into account a July 6 motion from the Dutch House of Representatives calling the bill “unacceptable.”

“To the extent the State Department enunciates concerns about JASTA’s adverse impact upon sovereign immunity of important US allies,” the letter states, “the enclosed binding motion associates the Dutch parliament with the expression of those concerns.”

The motion is particularly noteworthy because the Netherlands can hardly be accused of any kind of knee-jerk alignment with Saudi Arabia. The Dutch parliament voted to ban arms exports to Riyadh in March out of concern over Saudi actions in Yemen, making the Netherlands the first country to adopt a motion by the European Parliament in February urging an EU-wide Saudi arms embargo.