At least seven workers have died in a tunnel collapse in the northern Indian hill state of Uttarakhand, officials said on Friday, adding that a search was underway for three missing people.

The incident occurred overnight when a landslide sent water and debris streaming into an under-construction tunnel belonging to Tehri Hydro Development Corporation Limited (THDC) in Pipalkoti, in Chamoli district.

According to officials, 22 workers were inside the tunnel at the time of the disaster.

The injured are undergoing treatment.

A multi-agency effort is underway to reach the three workers still trapped inside the tunnel, with teams from the National and State Disaster Response Forces, the Indo-Tibetan Border Police and fire services at the site.

Rescuers are battling rising water and debris during the search, as the state has seen heavy rainfall in recent days.

Visuals circulated by local authorities show rescue teams wearing head-mounted torches and using makeshift rafts to reach the flooded section of the tunnel.

Uttarakhand Chief Minister Pushkar Singh Dhami visited the collapse site on Friday morning and reviewed the rescue operations.

"Evacuating every worker safely is our topmost priority," Dhami said in a statement.

In 2023, a tunnel collapse in Uttarakhand left 41 workers trapped for 17 days before they were rescued.