The cache, found in room 1014 on the 10th floor of Sri Bamrung Mueng Apartment in Soi Charan Sanitwong 53, included a hand grenade, a power-gel explosive bar, four detonators, three bullets for a .38 revolver and three bullets for a 9mm automatic pistol.

The headbands were yellow with the phrase "Save the Country" written in red, a type seen widely in press reports and worn by anti-Thaksin protesters. Another headband was plain green.

The room was rented by a woman for five months and then abandoned. The cache was found by the apartment managers after housemaids were assigned to enter the room for cleaning.

The room had been leased by a man who is now being sought by the police.

Metropolitan Police Bureau chief Pol Lt General Adisorn Nonsee spoke about the cache a few hours after it was found at 11.30am yesterday. He said the material looked to have nothing to do with the bomb attacks in Bangkok on New Year's Eve, or two other blasts, including one recently near Soi Rajavitee 24.

"The explosives found and the types used in the bomb attacks are different. Those were types with low explosive affects," he said.

Adisorn said police had yet to determine whether the discovery had anything to do with an attempt to kill the ousted prime minister with a car bomb last year at Bang Phlat Intersection, which is nearby.

He said a team of investigators had been set up to hunt down both unidentified persons. The police would not jump to a conclusion that the cache had something to do with leaders of the anti-Thaksin movement or that it was a set-up motivated politically to discredit it, he said, until both people were found and questioned.

The officer said anyone could have had the headbands in their possession or left them in the room deliberately to cause confusion.