Three astronauts, including a Russian and an American, touched down safely on Earth Wednesday aboard a Soyuz capsule, the first such landing since Russia's relationship with the West slumped amid the Ukraine crisis.

The returning crew consisted of Japan's Koichi Wakata, who was the first ever Japanese commander of an ISS space mission, as well as NASA astronaut Rick Mastracchio and Russian cosmonaut Mikhail Tyurin.

They landed safely at 0159 GMT in the Kazakh steppes after spending more than half a year aboard the orbiting International Space Station.

The landing was the first since Russia's relationship with the West hit its lowest point in decades over the annexation of Ukraine's Crimea peninsula by Moscow in mid-March and its involvement in the ensuing Ukraine crisis.

NASA in April announced that it was cutting space cooperation with Russia over Moscow's Ukraine policies, but that work at the space station would not be affected.

In what appeared to be a retaliatory move, Russia's deputy prime minister Dmitry Rogozin said Tuesday that Moscow had no plans to keep the station past 2020, even though NASA said in January that the administration of Barack Obama has extended the station's lifespan to 2024.

Use of the space station depends on Russia, which is the only country in charge of transporting astronauts and cosmonauts to and from the station.

The ISS was launched in 1998 as an international effort and has been a symbol of cooperation, particularly between the US and Russia. When the time comes to retire it, the station will be de-orbited and sunk in the ocean.

At a press conference on Tuesday Wakata thanked the three-man crew staying behind with the ISS and formally handed over the command to US astronaut Steve Swanson as the two floated the microphone to each other in the cramped space surrounded by crewmates.

Swanson's crew now comprises Russia's Alexander Skvortsov and Oleg Artemyev. They will be joined later this month by American Reid Wiseman, Germany's Alexander Gerst and Russia's Maxim Surayev.

"Folks, my last tweet from space. Stay tuned for post-flight fun," Mastracchio tweeted Tuesday several hours before the hatch on the departing Soyuz was closed.

Research conducted by the crew during the course of their 188-day stint in space included growing vegetables, investigating the design of medical drugs and studying how an astronaut's biological clock is different from that of a human on Earth.