The People's Alliance for Democracy (PAD) yesterday announced a new round of its crusade against Thaksin Shinwatatra, calling a huge protest next Friday after an accusation that the caretaker Prime Minister was challenging the monarchy.

"It's time to show our power to protect democracy," said PAD spokesman Suriyasai Katasila shortly after PAD leaders including Sondhi Limthongkul and Chamlong Srimuang reached consensus in a meeting yesterday.

The leaders had huddled earlier in the day to plan a response to recent Thaksin allegations of a plot to overthrow the government.

Thaksin launched a verbal attack last week on an anonymous individual he termed "a person with clout beyond the Constitution".

Many people assumed Thaksin was referring to the "most revered person in the country", Suriyasai said.

Thaksin refuses to name the person, in spite of repeated calls from many to do so.

The prime minister has since distorted his comments by referring to the person as the PAD, the news media or opposition parties, which has not eased tension, Suriyasai said.

"We will rally on Government House to pressure Thaksin for an explanation of who this person is," he added.

D-day is Friday, July 14, which is the anniversary of the formation of the Thai Rak Thai party, PAD sources explained.

It is understood some protesters are preparing to blockade Thai Rak Thai headquarters.

Suriyasai alleged Thaksin had insulted the monarchy and needed to see a show of people power.

The rally will start at Sanam Luang at 8am. Demonstrators will commence marching to Government House at 9am.

Suriyasai promised a peaceful demonstration. The group will decide on Friday how long the demonstrations will last.

The PAD decision to recommence street protests followed demands by media tycoon Sondhi on Wednesday for the public to take sides, for the monarchy or for Thaksin.

This has been criticised by academics and senators.

They asserted it was improper to drag the monarchy into politics and unnecessary disputes.

"We are all with His Majesty the King. We don't need to choose," Chulalongkorn University's Surichai Wangaeo said.

Government spokesman Surapong Seubwonglee on Thursday appealed to anti-government groups to cease dragging the monarchy into the political morass, saying nothing could be more improper or divisive.

He said Thaksin had not intended any reference to the monarchy in remarks last week to senior government officials and did not need to issue a clarification.

Senator Wallop Tangkananurak recommended the PAD turn its attention to getting new faces at the Election Commission rather than ousting Thaksin, who would be gone soon enough.

The PAD ceased its anti-Thaksin protests after the government said in early April that Thaksin would not resume the premiership, in spite of his triumph in the April 2 election.

Five weeks after the Administrative Court nullified the election result Thaksin was back in charge, saying a new election was several months away.

He said the country needed his leadership to fill an administration vacuum.

The PAD cried foul over his return and warned a new round of rallies would follow.

PAD sources said the alliance was struggling to recreate the volume of pre-election support as many now felt uncomfortable with the style employed by Sondhi.

Finances are also a problem, they said, as Sondhi's cash flow was dwindling with donations to the PAD having slimmed since March.

In a related development, outgoing Senator Kraisak Choonhavan last night claimed that Thaksin had in April sent a "secret letter" to US President George W Bush complaining about an alleged attempt to derail Thailand's democracy, something similar to what Thaksin said during a recent gathering of senior government figures.

Kraisak said he had learned of the letter from his sources in the Foreign Ministry and Government House. He was speaking during the "Muang Thai Rai Sapda" ("Thailand Weekly") meeting held at Lumpini Park.

Relevant government figures and US Embassy officials could not be reached last night for comment.

Meanwhile Network of People's Power for Democracy leader Surapong Towijakchaikul yesterday filed a complaint with police chief General Kowit Watana.

He is seeking action against Sondhi for refusing to report to the police over allegations of attempting to topple the government.

He also cited Sondhi and PAD leaders calling for the public to side with the monarchy or Thaksin.

In a further development, the US chapter of the PAD has asked all overseas Thais to protest on Sunday in front of their embassies.

The movement said in a Wednesday statement the rallies would protest at Thaksin's controversial overthrow comments.

It was not the first time Thaksin has made these kinds of remark, the statement said.