Booster rockets carrying a Soyuz spacecraft with a Russian and a USA astronaut on board headed for the International Space Station failed mid-air, forcing the crew to make an emergency landing, Russian news agencies have reported.
The pair were said to be in good condition after landing in Kazakhstan.
Roscosmos is forming a state commission to investigate the incident, Dean said.
While the initial launch at 04:40am ET was successful, the problem with the booster soon became apparent.
Russian Federation may indefinitely postpone its next manned Soyuz launch planned for December, state-owned RIA Novosti reported, citing an unidentified person.
Eleven minutes later, it added, "The crew is returning to Earth in a ballistic descent mode", meaning that it was falling without propulsion and that its direction was determined only by the craft's momentum.
Two astronauts have made an emergency landing after the rocket they were travelling in malfunctioned.
"The crew is alive and is landing in Kazakhstan", a source told the Russian news agency Interfax.
Search and rescue teams were deployed to the landing site.
That meeting comes in the midst of a continuing investigation by Roscosmos into a small air leak detected on a Soyuz capsule docked to the International Space Station in August, which was quickly patched and never posed a threat to the astronauts on board.
Thursday's aborted mission is another setback for Russia's space program.
Observers noted that the staging looked a bit odd, with the usual Korolev Cross (named for the designer of the ICBM on which the Soyuz booster is based) followed by what appeared to be debris as the stages separated.
Hague and Ovchinin were expected to spend six months on the station working on a range of scientific experiments.
Relations between Moscow and Washington have sunk to post-Cold War lows over the crisis in Ukraine, the war in Syria and allegations of Russian meddling in the 2016 US presidential vote, but they have maintained co-operation in space research.
A couple minutes after liftoff, however, a frantic message - "Failure, failure, failure", blared across the live feed.