The police arrested five armed Thai Muslim militants at the Sentral station in Kuala Lumpur two weeks ago, according to a report.

The latest issue of international weekly Time , said the five were nabbed on March 9 in a secret operation involving scores of security officials.

"Perhaps in an indication of the sensitivity of the arrests, Malaysian police spokesmen denied they had taken place. But Time confirmed the incident with two Malaysian intelligence officials familiar with the case," read the report .

It is unclear what the group had intended to do in Kuala Lumpur, the kind of weapons they were carrying, and whether there were others who had slipped through the security net.

However, on the night of the March 9 arrests, an explosion occurred outside the Australian High Commission. The police later ruled out the possibility of a terrorist attack.

The next day, the US Embassy said in an advisory to US citizens here that it had been warned by the Malaysian government of an " anonymous, unverified threat " in the city centre.

But the Malaysian government denied that it had warned the embassy of a security threat and lamented that it could be an attempt to undermine overseas confidence in the country.

Intelligence sources told Time that the Thais' presence in Kuala Lumpur was a disturbing sign.

Angered by crackdown

It is believed that Malaysia's action in preventing southern Thai rebels from slipping over the border might have angered the militants.

"We were safe when Malaysia was seen as a place to hide," Time quoted a Malaysian intelligence officer as saying. "But now we are arresting militants, and they are angry."

The Time report also highlighted the seizure of a cache of sophisticated bombs during a mid-February raid on a safe house in Philippines that police claimed was maintained by Abu Sayyaf militant group.

It said that 12 C4 plastic explosive were recovered, expertly hidden in items such as toothpaste tubes and deodorant bottles.

"We call them invisible bombs because they are very, very difficult to detect," one senior government official told Time . "And at that size we can only think of one purpose: airplanes."

According to the international weekly, the bombs - some of which already had detonators attached - represent a new level of danger for Asia's aviation industry.

Contacted by malaysiakini later, Deputy Inspector-General of Police Musa Hassan denied the report.

He said to his knowledge there was no such incident.