"The launch had a problem with the booster (rocket) a few seconds after the first stage separation and we can confirm now that the crew has started to go into ballistic descent mode", the voiceover on a NASA livestream from mission control in Houston said.
Both crewmembers were aboard a Russian-made Soyuz rocket bound for a six-month stay on the International Space Station when their rocket malfunctioned, forcing an abort of the mission and sending Hague and Ovchinin on an extreme ride back to Earth within the crew capsule.
The spacecraft, with United States astronaut Tyler "Nick" Hague and Russian cosmonaut Alexey Ovchinin, had taken off from the Baikonur cosmodrome in Kazakhstan and was less than two minutes into its flight an automatic abort command was triggered, leading to a fall of about 51 kilometres.
The engines were seen to cut out, after which the Soyuz MS-10 spaceship holding Russian commander Alexey Ovchinin and Nasa astronaut Nick Hague jettisoned from the drifting launch vehicle.
After the booster failed, Ovchinin and Hague were forced to make a ballistic descent, coming back to the ground at a sharper angle than normal and causing higher gravitational forces on their bodies.
Search and rescue teams were deployed to the landing site. The crew landed about 20 kilometers east of Dzhezkazgan, Kazakhstan, where rescue crews were scrambled to find them.
Unmanned launches of the Progress spacecraft - which carry food and other supplies to the ISS and use the same rocket system as Soyuz - might also be suspended, Interfax has said.
NASA and Roscosmos, the Russian space agency, pledged a thorough investigation after the aborted launch of a Russian Soyuz rocket.
Bridenstine, who is visiting Russia and Kazakhstan for the first time since his appointment as Nasa chief this year, observed the launch from Baikonur cosmodrome with his Russian counterpart Dmitry Rogozin. The capsule landed safely, and the two were recovered by emergency personnel.
The three astronauts now on board the space station have been informed of the failed launch and their schedule for the day is being reshuffled, since they'll no longer be able to greet the incoming duo.
Some have sarcastically linked the failed launch with the news Ukraine has made progress in trying to make its Orthodox Church independent of Moscow.
In August, the International Space Station crew spotted a hole in a Russian Soyuz capsule docked to the orbiting outpost that caused a brief loss of air pressure before being patched.
What went wrong? The Russian Soyuz rocket malfunctioned on lift-off. -Russian cooperation in space.
The European Space Agency is making contingency plans for three current space station crew members - German Alexander Gerst, American Serena Aunon-Chancellor, and Russian Sergei Prokopyev.