The Trump administration is expected to soon announce that it plans to exit the “Open Skies” treaty, a US official tells CNN, a move that has already drawn condemnation from Democrats in Congress.

The treaty, which was signed in 1992 and went into effect in 2002, allows 34 member states to conduct unarmed surveillance flights over one another’s territories. According to the State Department, the treaty “is designed to enhance mutual understanding and confidence by giving all participants, regardless of size, a direct role in gathering information through aerial imaging on military forces and activities of concern to them.”

In a statement, a State Department spokesperson said they were aware of Democratic lawmakers’ letters regarding the treaty.

“We do not comment on Congressional correspondence. We continue to implement the treaty and are in full compliance with our obligations under this Treaty, unlike Russia,” the spokesperson said.

The White House and Pentagon have not responded to CNN’s requests for comment on the matter.