They said the demand was made without a hidden agenda and should be viewed as a "danger sign".

Chat Thai deputy leader Somsak Prissanananthakul said Thaksin should consider the academic coalition's plea "a voice from heaven". He should make a decision about his political future accordingly.

Somsak believed Saturday's statement from the coalition illustrated dissent had reached every section of society and the situation could worsen to a point where Thaksin was unable to rule even as prime minister.

More than 40 academic groups called on Thaksin to resign from all political activity immediately and allow an investigation into alleged abuses of power. The scholars warned ignoring their calls could lead to civil war.

Democrat spokesman Ong-art Klampaiboon said the groups carried weight. They were the nation's intellectual elite and were expressing a political stand.

"The prime minister must listen to these calls with an open mind. These academics have expressed their opinion without conflict of interest as they simply want to protect the public," Ong-art said.

The Democrat spokesman said the coalition's stand was a warning sign Thaksin must acknowledge.

Ong-art warned Thaksin not to dismiss the academics as a "minority". They held an important role in society.

The Democrat Party was not behind the coalition's move and it would fully contest the October election and was confident of forming the next government, he said.

However, Thai Rak Thai dismissed the coalition's demand.

Spokesman Sita Divari said yesterday the opinions of academics would not affect political decisions made by the prime minister.

He advised voters to pay the coalition no mind as well as ignore the opinions of former prime minister Anand Panyarachun and Privy Council President Prem Tinsulanonda. The pair has made recent statements seen as attacking Thaksin.

Sita believed Prem would not step deeper into politics although the academic groups would call on him to make a clear-cut stand against the Thai Rak Thai leader.

Thaksin yesterday left his Charan Sanitwong Road residence to visit The Emporium shopping mall in the early afternoon amid stepped-up security.

He used two official cars to confuse reporters covering his activities. Thaksin's security detail asked the news media not to follow because the prime minister was on a private outing.

Reporters identified at the department store by the security officials were asked to leave the prime minister alone.