THE STAKES rose in Bangkok this afternoon as thousands of red shirt protesters attempted to end the government of Prime Minister Abhisit Vejjajiva by massing on the streets.

There were reports, confirmed by officials, that two Army personnel had been injured in a grenade blast at 1.30pm at the 11th Infantry Regiment headquarters.

Red shirt leaders also announced a plan to take blood donations from protesters, then smear the blood outside Government House.

The mass red shirt demonstration, peaceful since Friday, appeared to be fraying at the edges this afternoon.

Mr Abhisit and his fugitive rival, former PM Thaksin Shinawatra, both made strong pleas to the crowd, but for different outcomes.

The test will be whether frustration will see radicals within the red shirts go for broke, because another opportunity to depose the government may not arise.

Onlookers also pondered how the march will end, and when.

In a nationwide telecast as demonstrators converged on the government's secure base at the 11th Infantry Regiment headquarters, Khun Abhisit said: ''Asking for the dissolution of Parliament before noon in exchange for a halt to the demonstrations, we all agreed it can't be done.

''However, it doesn't mean the government coalition parties and I won't listen to their ideas.''

Last night, speaking via webcam from outside the country, Khun Thaksin told the protesters: ''The people who caused the problems in the country these days are the ruling elites. To solve problems related to democracy, equality and justice - the ruling elites won't be able to do that because they don't have the conscience.

''The people will have to do it.''

After darkness falls tonight, can police and soldiers expect outbreaks of violence? If the PM fails to make any concessions, will the vast crowd of red shirts be content to go home without achieving victory?

Numbers are well down on the ''million march'' concept, with the tally of protesters reckoned by many observers to be about 150,000 or less. Organisers put the figure at 300,000.

Phuket red shirt leaders told Phuketwan that about 500 supporters had made the trip to Bangkok, and were prepared to stay in the capital as long as necessary to achieve their aim.

Scandasia.com reports that Danish Star Tours on Phuket has cancelled the usual two-day trips to Bangkok for their guests.

Most Danish tourists take the opportunity to see the ''truly amazing'' Bangkok, but Stig Elling of Star Tours said: ''The excursions are cancelled now. We believe that's the right thing to do.''

Guests will go instead to Hua Hin or other destinations. Star Tours currently has about 1000 Danish guests on Phuket.

Hong Kong has kept its Outbound Travel Alert for Bangkok and surrounding areas at red since last Wednesday, and officials say the alert will be raised if necessary.

About 30 countries have issued warnings for tourists about Bangkok. But many tourists were continuing to explore the capital's attractions today without any idea that there was a face-off taking place.

A report in the English-language Korea Herald today says: ''The latest demonstrations show that once-stable Thailand has become the center of chronic unrest. It is high time that the people of that wonderful country, through their elected representatives and political parties, worked something out so that the clashes can finally end.

''Everyone needs to realise that if these conflicts continue to go on with no end, tourists and investors will gradually give up on Thailand and go elsewhere.''