The US space agency has renewed a contract to use Russian spaceships to ferry astronauts to the International Space Station (ISS) up to 2016, the Russian space agency said Tuesday.

The Russian agency said the two sides had signed a contract for Russia to transport 12 astronauts on its in the period between 2014-2016. put the value of the contract at $753 million.

Six astronauts will fly out in 2014 and six in 2015 for six-month stints on the ISS, with the last astronauts returning in 2016, NASA said in a statement published on its website.

The Soviet-era Soyuz capsules, which can only carry three , will provide the only link for human travel to the ISS after the US shuttle programme closes later this year, at least until 2016.

Russia announced a delay Monday in the latest launch of a Soyuz spaceship planned for March 30 due to a technical problem with the spacecraft.

The delay was an embarrassment as the launch was timed to celebrate the forthcoming 50th anniversary of the first manned space flight by Yuri Gagarin, still a huge source of national pride.