At least 168 people have been killed and over 745 injured after a tsunami hit the coast on Indonesia's Sunda Strait, reported BBC citing senior government officials. The possible cause of the tsunami was undersea landslides after a volcano erupted.

The country's disaster management agency said hundreds of buildings were damaged by the tsunami.

It says the possible cause of the tsunami was undersea landslides after the Krakatoa volcano erupted.

The strait, between the islands of Java and Sumatra, connects the Java Sea to the Indian Ocean.

The disaster management agency warned that the death toll after the tsunami, that struck at about 21:30 local time (14:30GMT) on Saturday, is likely to rise further, said the report.

Deaths have been reported in the Pandeglang, South Lampung and Serang regions.

In a Twitter post, President Joko Widodo expressed his “deep sorrow” for the tsunami victims and said he had ordered the relevant government agencies to respond to the emergency.

Videos from the regency of Pandeglang in Java’s Banten Province showed extensive damage, and officials said the road from Pandeglang to the nearby regency of Serang had been cut off.

Among the areas hit was the popular Tanjung Lesung beach resort in west Java. There was no warning of the advancing wave.

Footage shared on social media showed a large wave crashing into a tent in the resort, in which a popular Indonesian rock band, Seventeen, was performing. Members of the band were seen being swept away as the wave destroyed the stage.

In an Instagram video, singer Riefian Fajarsyah, said the band's bassist and road manager had died, and that three other band members and his own wife were missing.

The country's Red Cross said it was on the scene and searching for victims in the rubble of one collapsed building.

Over 400 buildings have been destroyed as waves slammed into the Sunda Strait, which separates Indonesia’s two largest islands, Java and Sumatra, reported The Washington Post..

Beaches in the strait were reported heavily hit in places such as the Pandeglang regency, where 33 were reportedly killed, or several beaches like Anyer or the Tanjung Lesung.

Oystein Lund Andersen, a Norwegian witness who was on a family trip on the coast of the Anyer beach, wrote on Facebook that he was on a family trip when he saw the incoming wave.

“Next wave entered the hotel area where I was staying and downed cars on the road behind it. Managed to evacuate with my family to higher ground through forest paths and villages, where we are taken care of by the locals. Were unharmed, thankfully,” he wrote.

Government officials are warning tourists against visiting the beaches near the Sunda Strait.

“The national disaster agency and the geology agency are still investigating [the tsunami],” Nugroho said. Nugroho also added that heavy equipment and emergency soup kitchens have been prepared.

Indonesia’s volcanology and geology disaster mitigation center said there was an eruption of the Krakatoa on Saturday night.

Although there was a “300 to 1500 meter” ash cloud reported above the crater’s peak, the center said, it was unclear whether the tsunami was directly caused by the eruption.

Igan Sutawijaya, a volcano and geological disaster expert, said the Sunda Strait is a disaster-prone area but the waves may not be directly linked to an eruption.

“My suspicion is that there was an landslide under the sea. Perhaps a trench crumbled,” he told The Washington Post in a phone interview. “It doesn’t make sense that it was caused by the eruption of the Krakatoa.”

Indonesia sits on the seismically active “ring of fire” in the Pacific Ocean, he added.