Two Singapore fighter jets escorted a commercial airliner back to Singapore on Thursday due to a bomb threat that turned out to be a hoax, according to Singapore police.

Flight TR634 carrying 173 passengers and six crew and operated by the Singapore-based low-cost airline Scoot landed safely at Changi Airport about two hours after departing on a flight to Hat Yai, Thailand.

Singapore police said in a statement that a 41-year-old man had been arrested for making a false bomb threat.

"Preliminary investigations indicated that the suspect had claimed to crew that he had a bomb in his hand-carry baggage," the police statement said.

Authorities conducted a thorough search of the plane and the baggage of the suspect and his two male traveling companions but did not find any bomb, the statement said.

The suspect has been arrested under legislation that makes it crime to threaten to commit a terrorist act and carries a fine up to $500,000 and possible imprisonment for up to 10 years.

Singapore is on heightened alert against terrorism, as it believes it could be targeted due to its close relations with the United States and Israel.

The Singapore Terrorism Threat Assessment Report 2017, issued last June by the Ministry of Home Affairs, said Islamic State militants "were considering carrying out an attack in Singapore in the first half of 2016," while Indonesian authorities had foiled a plot by terrorists "acting on the instructions ... of an Indonesian ISIS militant based in Syria ... to launch a rocket attack against the Marina Bay Sands" resort in Singapore.