BANGKOK, April 17 (Xinhua) -- Photos and video of a western man with injuries who claimed he was bitten by a shark at a beach in southern Thailand's Hua Hin went viral on social media.

Warning signs have been set up to keep tourists away from deep sea though local authorities remained uncertain whether the man suffered a shark attack or was injured by sharp rocks, local media reported on Tuesday.

In the clip posted on Sunday, the man carried out from the water was suffering multiple injuries to one of his feet. He was then hospitalized.

The clip was followed by photos of more than 10 sharks at a beach in the south of the famous seaside destination, urging local authorities to conduct further survey.

The shark from the clip was probably small black tip reef shark less than two meters long, which has never reported in attacks on humans in Thailand, said Thon Thamrongnawasawat, deputy dean of Kasersart University's Faculty of Fisheries.

Thon said shark attacks in Thailand in the past 20 years happened mostly when sharks swam to shore assumed that victims' legs might be other fish and tried to bite.

Big shark such as white shark is never found in Thailand, said Thon, adding that sharks most dangerous to humans such as tiger shark could be hardly seen in Thailand in the two decades.