Russian officials say four Russian mountaineers are in very serious condition at a hospital in Dushanbe after a deadly August 13 helicopter accident in Tajikistan's Pamir Mountains, according to Radio Liberty’s Tajik Service.

The Russian Embassy in Dushanbe said four of the 10 Russian mountaineers who survived the crash sustained “very serious” injuries.

Tajikistan's State Emergency Committee said earlier that three Russian mountaineers – Alexander Abrosimov, Ruslan Tarakanov, and Timur Barabanov -- were killed in the crash along with two Tajik members of the helicopter crew.

The committee said the Mi-8 helicopter was carrying 13 Russians, one Belarusian, and one Spanish mountaineer after they reached the Ismoili Somoni peak, the highest in the former Soviet Union. The Belarusian and Spanish mountaineers both survived but were also hospitalized.

Tajik authorities say bad weather conditions may have contributed to the accident.

The Interior Ministry said it launched investigations into what it described as the helicopter's "crash-landing."

Tajik President Emomali Rahmon has expressed condolences to Russian President Vladimir Putin about the crash.