Thai police on Friday said Moscow’s top intelligence agency has warned a group of 10 militants from the self-styled Islamic State has entered the kingdom to target Russians, according to AFP.

A leaked letter, marked “secret” and “urgent” and signed by the deputy head of Thailand’s special branch, was widely circulated on local media late Thursday.

It said Moscow’s Federal Security Service (FSB) has told Thai police that 10 Syrian militants from Islamic State entered the country between October 15 and 31 to target Russian interests.

Thailand is a major holiday destination for Russian tourists, particularly during the peak Christmas and New Year holidays.

“They (the Syrians) travelled separately. Four went to Pattaya, two to Phuket, two to Bangkok and the other two to (an) unknown location,” the letter said, citing the information from Russia’s top intelligence agency.

“Their purpose is to create bad incidents to effect Russians and Russia’s alliance with Thailand,” the letter said, without naming the suspects.

A deputy spokesman for the Thai police said, “the letter is real”.

“So far it’s only intelligence news that still needs to be proved… we have no proof if they are here for real or not,” Songpol Wattanachai told reporters.

“Please be confident (in Thailand) — we won’t disregard the intelligence.”

Thailand is in its peak holiday season when international arrivals surge, bringing huge sums of money to the economy.

According to Bangkok Post, as news of the IS group threat spread, Thai officials on Friday lined up to urged restraint and call for further verification of the information.

Maj Gen Banpot Poonphien, the Internal Security Operations Command spokesman, noted that Thailand is not the party to any direct conflict the Islamic State group.

But with a raging Muslim insurgency in the Far South, the threat of an Islamic State group incursion into Thailand has been a continual worry. Yet just last month, Gen Thawaip said no IS members had come to deep South.

“The intelligence community, including our neighbouring countries, insist no IS members have entered the southern border area of Thailand,” he said Nov 18.