Colombo, Over 100 stranded whales, swept ashore on Sri Lanka's beaches, were rescued on Tuesday and pushed back to sea after a nearly 18 hour rescue mission, the navy said.

Navy spokesperson Captain Indika De Silva told Xinhua news agency that nearly 120 whales had been washed ashore on the Panadura beaches, just on the outskirts of capital Colombo, on Monday and the navy as well as the coast guard were immediately alerted by residents in the area.

This was Sri Lanka's largest mass stranding of whales, marine biologists said.

Nearly 70 navy and coast guard personnel along with civilian groups had been involved in the rescue mission and the last whale was pushed back to sea by 8 a.m. on Tuesday.

"We worked throughout the night and by the morning we successfully pushed the last animal into the sea. A lot of civilian groups also assisted us. Unfortunately, we found four carcasses," De Silva said.

The carcasses had been found on the Panadura beaches and the beaches of Wellawatta and Wadduwa.

Marine biologists are conducting investigations on how the whales had been washed ashore.