The military added that "Russia's unprovoked attack" on Ukrainian ships near the Kerch Strait on November 25 is "a unsafe escalation in a pattern of increasingly provocative and threatening activity".
"The United States seeks a better relationship with Russian Federation, but this can not happen while its unlawful and destabilizing actions continue in Ukraine and elsewhere", the Pentagon said in a statement Thursday. The objective to is promote transparency in military activities. But the treaty also permits 'extraordinary, ' or extra, flights if two participating members agree.
"Today, the United States and Allies conducted an extraordinary flight under the Open Skies Treaty". Following their detention by the Russian authorities, Ukranian President Petro Poroshenko introduced martial law in all regions bordering Russia as well as the coasts of the Black Sea and the Sea of Azov.
The Pentagon condemned Russia's actions, adding the timing of the flight was intended "to reaffirm US commitment to Ukraine and other partner nations" and that the U.S.is "resolute" in its support of the security of European nations.
U.S. Defense Chief Accuses Putin Of 'Duplicitous' Action On Missile Treaty
Trump abruptly canceled a planned meeting with Putin at the summit just two days before they were scheduled to sit down. Ambassador Nikki Haley in response to the actions.
Pahon said the plane that was flown over Ukraine on Thursday was an OC-135 observation aircraft with U.S., Canadian, German, French, British, Romanian and Ukrainian observers aboard.
Pahon said the plane had a 17-member crew from the 55th Wing based at Offutt Air Force Base in Nebraska. The observation flight was requested under the Open Skies Treaty by the Arms Control Directorate of the Ukrainian General Staff.
The treaty "promotes openness and transparency in military activities through reciprocal, unarmed observation flights", Pahon said.
It flew from Andrews Air Force Base in Maryland to Ramstein air base in Germany on November 30 and flew over Ukraine on Thursday, he said.