The National Disaster Management Authority said para-military officers were also on the helicopter.
Garud commandos have reached the site of the crash and will have more information soon, said Air Force sources.
Within minutes of the crash, the Air Force said its rescue operations would continue as planned, illustrating the heroism and sacrifice that has suffused its largest relief and rescue mission ever.
The Air Force said the helicopter that crashed this evening had been sent on a rescue mission from the town of Gauchar, serving as a hub of relief and rescue operations, to Guptakashi and Kedarnath, the epicentre of the devastation caused by torrential rains in the hilly state.
60 air force helicopters are being used along with some privately-owned ones.
Prime Minister Mamohan Singh offered his condolences, saying "Our forces are conducting a heroic task in rescue and relief work in Uttarakhand. ... Continuing their work would be the best homage to them," he added. (Read: PM shocked at deaths in helicopter crash)
The risk under which the Air Force is flying through treacherous terrain, air-lifting pilgrims and air-dropping commandos and soldiers to temporary camps was on display all day today. Each time the rain let up, or the cloud cover improved, helicopters would head out. (How you can help)
Yesterday, as the met department issued a warning of severe rain in Uttarakhand for three days, Air Chief Marshal Browne offered this statement of reassurance: "Our helicopter rotors will not stop churning till such time we get each one of you out, do not lose hope and hang in there."
More than 90,000 people have been evacuated so far in efforts led by the military.
The type of helicopter that crashed today - the Mi-17 V5 - was inducted last year; 80 helicopters were ordered from Russia.
On Monday, a private helicopter crashed in Gaurikund and was on fire when an Air Force helicopter on a rescue mission nearby swooped in to rescue the pilot.