US military plane makes emergency landing on Russian airstri

Washington (CNN)At the same time that political tensions between Washington and Moscow were raging this week, the US and Russia calmly handled the emergency landing of a US military aircraft in western Siberia, according to the Pentagon.

The incident occurred Wednesday when the landing gear of a US observation flight malfunctioned and the plane had to make an unplanned landing in a Russian airstrip near the Chinese border.

The OC-135B observation aircraft had taken off from a Russian airfield at Ulan Ude for a scheduled observation flight conducted under the terms of the Open Skies Treaty.

That treaty allows both countries to fly unarmed observation aircraft over each other's territory. The flights are intended to be confidence-building measures and are subject to provisions for openness and transparency on the information being collected via cameras and other sensors.

On this mission, the US aircraft -- with Russian observers on board -- took off to start its designated observation flight plan, but the aircraft landing gear did not retract.

The US commander, in cooperation with the Russian escort crew on board diverted the aircraft to Khabarovsk "so the aircraft could exit Russia in the most direct route possible," Pentagon spokeswoman Lt. Col. Michelle L. Baldanza told CNN. "Due to aircraft performance limitations associated with summer temperatures and the landing gear malfunction, the Khabarovsk runway represented the only safe location to land."

That airfield is not normally used under the treaty for US aircraft to exit out of Russia.

The Russian on-board crew verified that no imagery was collected during the flight and the aircraft then flew on to Japan, where it is being repaired.

The Pentagon was adamant this was not a spy mission because all portions of the flight and sensor equipment on board are open to the Russians to observe.