U.S. Energy Secretary Rick Perry has approved six secret authorizations by companies to sell nuclear power technology and assistance to Saudi Arabia, reports Reuters.

The Trump administration has quietly pursued a wider deal on sharing U.S. nuclear power technology with Saudi Arabia, which aims to build at least two nuclear power plants.

Perry’s approvals, known as Part 810 authorizations, allow companies to do preliminary work on nuclear power ahead of any deal but not ship equipment that would go into a plant.

The Department of Energy’s National Nuclear Security Administration (NNSA) said in the document that the companies had requested that the Trump administration keep the approvals secret.

Many U.S. lawmakers are concerned that sharing nuclear technology with Saudi Arabia could eventually lead to a nuclear arms race in the Middle East.