Security has been tightened up at tourism spots and airports in Bangkok after reports another terror attack could be imminent.

An armed group may be plotting car bomb attacks in or near the capital, Thailand’s national security chief said.

“The deputy prime minister instructed security agencies to closely track and monitor anything unusual including things used to prepare bombs and cars,” said Thawip Netniyom.

“I have ordered all police under my supervision in the area around Bangkok to monitor news, investigate and gather intelligence on groups who could come in and cause trouble,” said acting head of Bangkok police, lieutenant general Charnthep Sesawet.

Thailand suffered a series of bomb attacks at four tourist destinations in August, killing four and injuring dozens of people, including foreign tourists.

Those attacks were eventually linked with Islamic separatists operating in Thailand’s south but security chief Thawip said authorities have not yet found a connection with those attacks and the latest threat.