MOSCOW, Dec. 12 (Xinhua) -- During an "unprecedented" spacewalk, Russian cosmonauts Oleg Kononenko and Sergey Prokopyev have found the hole on the Soyuz MS-09 spacecraft which caused a pressure leak at the International Space Station (ISS) in August, the Russian Mission Control Center (MCC) said on Wednesday.

Russian Space Agency Roscosmos Chief Dmitry Rogozin wrote on Twitter Tuesday that the spacewalk would be "unprecedented by its complexity."

"First, Kononenko removed part of the screen-vacuum thermal insulation, which covered the meteorite protection. After that, he cut the protective with snips and unbent it. Then he cut off the bent part (a piece about eight by eight inches) and put it into a container," the MCC was quoted the Sputnik news agency as saying.

Kononenko has to take two swipe samples from the hole area and then apply a patch piece and secure it with clips. The sample will be sent to the Earth for further study.

In August, cosmonauts of the ISS discovered a micro crack on the Soyuz MS-09 spaceship. The fracture was later patched from inside without astronauts going into outer space.

Russia's Soyuz spacecraft is currently the only vehicle for spaceflights between the ISS and the Earth.