Photographers, TV cameramen and passers-by watch from a distance as police bomb disposal experts defuse explosives found in a Daewoo sedan near the Bang Phlat intersection.

Caretaker Prime Minister Thaksin Shinawatra yesterday said he knew two weeks ago that someone wanted to kill him and had escaped yesterday's alleged attempt by changing his routine to deceive the potential assassins.

A security source said Thaksin suspected certain military figures to be behind the alleged bombing plot. Thaksin said he had been more careful since an "incident" at the military airport and a recent crash involving a car and a motorcycle from one of his convoys.

He said he had a called a meeting about flood prevention yesterday at 8.30am, earlier than expected, and then left his home ahead of schedule.

Thaksin said he would be making fewer public appearances until the investigation into the incident was completed.

Asked if he was scared of assassination, Thaksin said a human is born once and dies once. "My family must be careful," he said.

Thaksin simply laughed when asked if what happened yesterday would affect his decision on whether to quit politics.

The deputy chief of the Internal Security Operations Command (Isoc), Pallop Pinmanee, was promptly sacked on the prime minister's orders yesterday as it was believed at least one suspect in the incident is a close aide of Pallop's and works under the Isoc.

Asked if the decision to sack Pallop was related to the alleged assassination attempt, Thaksin said he could not say until the investigation was over.

Asked what his next moves were, Thaksin did not reply but asked reporters, "Isn't it unbelievable?"

Thaksin yesterday cancelled his entire afternoon schedule and convened a meeting with armed forces commanders and relevant Cabinet members at Government House.

According to a source, Thaksin told the top brass during the meeting that he was lucky to have left home earlier than usual to attend a meeting on flooding in the North. He said that judging from the explosive components, the bomb could have had enormous impact on nearby areas.

Thaksin said his security detail had twice earlier spotted a Daewoo car similar to the one found carrying explosive components yesterday.

The source said Thaksin told the generals that he had become a target for assassination possibly because he had been prime minister for too long.

"The perpetrators are the same group that committed a similar plot before [with a long-serving government leader]," the source quoted Thaksin as saying.

Government spokesman Surapong Suebwonglee said that police were investigating who was behind the incident and, if concrete evidence is found to connect anyone to a possible assassination attempt, additional safety measures would be implemented.

Surapong said the government regarded the incident as an attempt by a group that wanted to create a disturbance.

He would not comment on whether the incident was politically motivated but called for a constructive political atmosphere, saying that assassinating someone was the wrong way to do things.

"There are two groups with different political opinions. But today a group resorted to violence and destruction and that is ugly and disgusting. We must condemn them," Surapong said.

Surapong said Thaksin was not scared by the alleged assassination attempt but was being more cautious. State security agencies had tipped off the prime minister earlier about a possible assassination attempt, he said.

He said caretaker Defence Minister Thamarak Isarangura yesterday led a delegation of leaders of the armed forces to offer Thaksin moral support after the news broke about the alleged bombing plot.