A woman walks a dog near the U.S. Capitol building in Washington D.C., the United States, May 15, 2020.(Xinhua/Liu Jie)

"It appears that short-sighted interests and partisan politics prevailed over reason and good foreign policy. This is a regrettable decision that will have lasting consequences."

WASHINGTON, May 23 -- U.S. Democrats on Friday denounced the Trump administration's decision to withdraw from the Open Skies Treaty, saying it's illegal and demanding an explanation.

In a letter to U.S. State Secretary Mike Pompeo and Defense Secretary Mark Esper, House Foreign Affairs Committee Chairman Eliot Engel and Armed Services Committee Chairman Adam Smith said that the withdrawal from the treaty without consultation with Congress violates Section 1234 of the Fiscal Year 2020 National Defense Authorization Act.

"This provision of law stipulates that you must notify Congress not later than 120 days before the intent to withdraw from the treaty is presented to either treaty depository ... To date, this requirement has not been fulfilled," the two Democrats said in the letter, demanding an explanation for this "intended illegal action."

Engel and Smith also said that they strongly oppose the withdrawal decision, which they believe would "specifically negatively impact U.S. leadership in NATO and the transatlantic relationship with its allies and partners."

"It appears that short-sighted interests and partisan politics prevailed over reason and good foreign policy. This is a regrettable decision that will have lasting consequences," they added.