BANGKOK, Oct 7: Thai police arrested six men at an airport in southern Thailand and are questioning them over suspected terrorist links, police said Sunday.

Police in the southern city of Hat Yai said they had arrested three Iranians, two Iraqis and one Afghan for illegally entering Thailand, and found on them items that raised suspicions of terrorist connections.

Hat Yai Deputy Police Commander Noppadol Peuksophon said police were searching for additional suspects who may have crossed into Thailand from neighbouring Malaysia.

“The police have been searching ... trains and bus stations, after the six men were arrested (on) Friday with a cutter and tubes,” he said.

The men who were arrested late Friday at Hat Yai International Airport were carrying a small cutter, a 24-page document in Arabic and two small glass tubes that police have reportedly said may be part of an explosive device.

“We found a cutter on the Afghan that can be used as a weapon,” said police Colonel Suwat Pongpaiboon.

“We don’t know yet what they were preparing to use the electric tubes for. Specialists will be investigating what the electric tubes can do,” he said.

“We can’t say they are terrorists at the moment.”

Police have tightened security along Thailand’s southern border, with security checkpoints on roads in Sadao district, about 930 kilometres south of Bangkok, where the men said they entered the country.

Suwat said the men were fined 10,000 baht (228 dollars) and were being held as illegal immigrants for further questioning.

“They were detained by police because they don’t have money to pay for the fine,” he said. “They will be jailed for 142 days starting last Friday. They are detained as illegal immigrants.”

A US embassy spokeswoman told AFP that Thai officials were handling the investigation while providing information to US law enforcement agencies.

“We haven’t been involved in the investigation directly, but we’re aware of it and they’re keeping us informed,” she said.

Meanwhile, the Bangkok Post reported that an American-Indian engineer had been detained for questioning by police Saturday after he was found taking pictures of Bangkok International Airport. He was released after three hours.

The five predominantly Muslim provinces bordering Malaysia are home to a low-level insurgency which has dropped out of the headlines in recent years.

EVIDENCE PRESENTED: US ambassador to Thailand Richard Hecklinger on Sunday gave Thai Foreign Minister Surakiart Sathirathai evidence the US says links Osama bin Laden to the September 11 terrorist attacks on New York and Washington.