The Trump administration has made the final decision to withdraw from the international Open Skies Treaty, officials confirmed May 21.

The news, first reported Thursday by the New York Times, was confirmed by President Trump as well as Secretary of State Mike Pompeo. The administration has been threatening to leave the agreement for years, claiming that fellow member nation Russia has not always remained “in full compliance” with the treaty, which includes 34 nations and allows for mutual pre-scheduled reconnaissance flights over each other’s territory.

Pompeo said Thursday that the U.S. government may reconsider withdrawing should Russia return to full compliance. An emergency meeting of NATO members is scheduled for Friday, the same day the United States plans to make a formal notification of withdrawal.

Jonathan Hoffman, chief Pentagon spokesman, told reporters in a Thursday press briefing that Defense Secretary Mark Esper has shared concerns about Russia’s actions with other Open Skies Treaty members and allies since 2017.

“The United States does remain fully committed to agreements that advance U.S., allied and partner security, are verifiable and enforceable, and include partners that comply responsibly with their obligations,” he said. “What I can tell you is that Russia flagrantly and continuously violates its obligations under Open Skies, and implements the treaty in ways that contribute to military threats against the United States and our allies and partners. We have been clear on these concerns for years.”

Lawmakers on Capitol Hill responded to the news on largely partisan lines. Republicans expressed their support for the withdrawal including Senate Armed Services Committee Chairman Jim Inhofe (R-Okla.), who said in a statement that the Trump administration must make sure to continue to work with eastern European allies to ensure it retains access to high-quality imagery.

“I know there is concern among many of America’s friends that there are fewer arms control and confidence-building mechanisms in place today than in the past. That’s because of one person: Vladimir Putin,” Inhofe said.

Sen. Tom Cotton (R-Ark.), an Army veteran and chairman of the SASC airpower subcommittee, called the move “another positive step to end America’s dependence on dysfunctional and broken treaties.”

“The Open Skies Treaty started life as a good-faith agreement between major powers and died an asset of Russian intelligence,” he added.

Democratic lawmakers bemoaned the move as weakening U.S. national security interests and further isolating the nation. House Armed Services Committee Chairman Adam Smith (D-Wash.) and HASC Strategic Forces Subcommittee Chairman Jim Cooper (D-Tenn.) called the decision “a slap in the face to our allies in Europe, leaves our deployed forces in the region at risk, and is in blatant violation of the law” in a joint Thursday press release. Cooper and Smith also criticized the lack of notice given to Congress ahead of the announcement.

Senate Foreign Relations Committee Ranking Member Bob Menendez (D-N.J.) also blasted the move, saying “It is Congress’ constitutionally mandated duty to provide advice and consent on any treaty.”

“In last year’s [National Defense Authorization Act], Congress explicitly mandated the administration provide a review period to examine the administration’s decision before a formal withdrawal is commenced,” he said. “The administration has failed to follow the law by not providing Congress with this review period.”

Earlier this year, the Air Force requested funds to begin the recapitalization of the two aircraft used in Open Skies reconnaissance missions, the OC-135B. It was not made immediately clear what will happen to those requested funds, but Cotton called for the quarter of a million dollars to be put toward nuclear modernization efforts, calling them “a far more effective guarantee of peace between major powers than obsolete treaties.”