At least 14 people have been killed and 102 are still missing in the north-east Indian state of Sikkim after heavy rain caused a glacial lake to burst its banks, triggering flash floods down a mountain valley.

The disaster, which took place on Wednesday, has affected more than 22,000 people, according to the authorities, and 22 army personnel are among the missing. It has also left over 3,000 tourists stranded after the floods washed away the main highways and bridges.

The catastrophic overflow of Lhonak Lake took place after five times the usual amount of rain fell on the state during a cloudburst, causing a dam to partially collapse in the Teesta valley, close to the border with China. Video footage showed the muddy flood waters surging into built-up areas, causing houses to collapse and submerging army bases.

"The search operations are being undertaken under conditions of incessant rains, fast-flowing water in Teesta River, roads and bridges washed away at many places," a defence spokesperson said on the X social media platform, formerly known as Twitter.

Authorities warned the rescue operation would be challenging as more rain was forecast in coming days and mobile and phone lines continued to be down.

Sikkim flash floods: Death toll rises to 56, over 100 still missing

The disaster management authorities have confirmed 26 deaths in Sikkim so far. Four bodies were recovered from Mangan district, six from Gangtok, and 16, including seven Indian Army personnel, from Pakyong district.

According to the West Bengal government, they have recovered 30 bodies from three districts: Siliguri, Jalpaiguri, and Cooch Behar in the basin of the Teesta River.

The flash flood, which was triggered by a cloudburst in the early hours of Wednesday, led to severe destruction in Sikkim. It has affected over 25,000 people, damaged more than 1,200 houses and washed away 13 bridges, roads and other structures.

Meanwhile, the Ministry of Defence stated that military equipment including ammunition were washed away in the flooding.

"Due to severe floods in Sikkim certain military equipment including firearms and explosives were carried away in Teesta river.Urgent notice for public has already been issued by Jalpaiguri District Authorities. Army has established lookout teams all along the river downstream," the Defence Ministry said in a statement.

As many as 2,413 people have been rescued from different areas and 6,875 people are taking shelter in 22 relief camps set up across the state.

At least 77 people are confirmed dead in the floods that hit India's northeast, authorities said Sunday, with destroyed roads and bridges leaving thousands more still cut off despite waters receding.

Violent torrents struck Sikkim state on Wednesday after a high-altitude glacial lake suddenly burst.