Caretaker Prime Minister Thaksin Shinawatra yesterday denied that there was any move to launch a coup in Thailand.

Thaksin was speaking at the Asia-Europe Meeting (ASEM) in Finland.

"I've never said that there was any movement suggestive of a coup plan. From as far as I know, there's no such movement for the time being," he said.

However, he said rumours about a coup were indeed swirling because some people really wanted a coup to take place.

An army officer said to be the key suspect in a plot to assassinate Thaksin has allegedly implicated three more senior officers.

He is reported to have named three majors general and two sergeants.

They are alleged to have built the failed bomb in Lop Buri.

Sgt-Major Chakhrit Janthara, who surrendered to police last Wednesday, allegedly said majors general "Kor, Phor and Por" conspired in the assassination plot.

All three were assigned to the Internal Security Operations Command (Isoc) and were close to General Pallop Pinmanee. He was sacked as Isoc deputy director for "betraying" Thai Rak Thai, said a police source.

Chakhrit had previously implicated a four-star general as the plot mastermind. He implicated four other Isoc officers as accomplices.

According to the source, Chakhrit said in addition to the Daewoo sedan car bomb, officers had weapons hidden in a gold-bronze-coloured Nissan pickup in case the bomb failed.

The pickup was parked at a hotel at Thon Buri a few hours before the car bomb operation failed.

Weapons in the pickup were from a military unit in Lop Buri, the source said.

Police have yet to locate the pickup.

A source said police found explosives hidden in the Daewoo sedan were prepared by two sergeants of a military unit in Lop Buri.

Crime Suppression Division chief Police Maj-General Winai Thongsong said a police search of seven Bangkok homes of military personnel allegedly linked to the assassination plot uncovered only documents that may or may not be useful in the investigation.

Police yesterday upped security at the Crime Suppression Division where Sgt-Major Chakhrit is detained.

Police commandos guard him around the clock.

Special locks secure the division building and only high-ranking police and division officials are allowed to enter.