The Washington Post, citing U.S. officials, reported that confidential documents containing assessments by the U.S. intelligence community that have been provided to Congress show that Saudi Arabia has not ruled out expanding its nuclear weapons program.

This assessment has increased concerns among a number of U.S. lawmakers about the agreement by Donald Trump’s administration, the U.S. president, to help launch Saudi Arabia’s civilian nuclear program. Under this agreement, American companies could carry out nuclear energy projects worth tens of billions of dollars in Saudi Arabia.

A group of Democratic senators has also warned that the deal could allow Riyadh to gain the capability to enrich uranium. The U.S. State Department, in response, said Washington does not support a nuclear weapons program for Saudi Arabia and that the agreement preserves nonproliferation standards.

Saudi Arabia has also previously said its nuclear program will be peaceful and will be developed with “the highest levels of accountability and transparency.”