(Photo: Reuters)

Russian space agency Roscosmos said the launch had been successful and that the crew was expected to arrive at the ISS at 1323 GMT.

Fischer and Yurchikhin were originally assigned in 2015 to fly with a third crew member, ESA's Paolo Nespoli, but a decision by Roscosmos to reduce its contingent from three to two cosmonauts until its multipurpose lab module (MLM) Nauka is ready to launch in 2018.

Fischer and Yurchikhin will spend more than four months aboard the orbiting space station before returning to Earth in September.

The arrival of Fischer and Yurchikhin increased the station's crew complement to five. The two join Expedition 51 Commander Peggy Whitson of NASA and Flight Engineers Oleg Novitskiy of Roscosmos and Thomas Pesquet of ESA (European Space Agency). The Expedition 51 crew members will spend more than four months conducting approximately 250 science investigations in fields such as biology, Earth science, human research, physical sciences and technology development./.

Compiled by BTA