Hundreds of supporters of prime minister Samak Sundaravej and ousted premier Thaksin Shinawatra made their first attack on members of the People's Alliance for Democracy who have dug themselves into Government House in the Thai capital.
One person was killed and 40 injured in a series of street battles involving baseball bats, clubs and swords. There were reports of gunshot wounds.
The People's Alliance for Democracy remained defiant, with one of its leaders saying: 'We are staying until Samak and his party goes. There are not enough jails for us.'
Children were sent home from schools, workers went on strike and tourists, thousands of them British, struggled to get out of the country as main airports were shut down.
Then, Thailand's Election Commission, which has been investigating how Mr Samak came to power, made the announcement that this year's elections were rigged and he and his whole party should step down.
The Election Commission is taking Mr Samak's People's Power Party to the Constitution Court, claiming the party's deputy leader bought votes.
Crucial to any forthcoming battles is what role the Thai army and police will play. The People's Alliance for Democracy has been protesting for more than a week, demanding the resignation of Mr Samak who was elected as the nominee of Mr Thaksin, who had been indicted for corruption and is now in exile in Britain.
They claim that Mr Samak and his cohorts will enrich themselves and bleed the country dry in the process.
They want an end to Western-style democracy, because, they say, politicians are able to buy themselves into power.
They have successfully shut down most of the country's railway system airports at the tourist destinations of Phuket and Krabi in south Thailand for two days.
Police have failed to get the protesters out of their occupation of Government House and the army has declined to intervene.
In the last few days Thailand's police chief has been replaced and so has the commander in chief of the armed forces.
The army is expected to be called upon to enforce the terms of the state of emergency but as it was the army which ousted Mr Thaksin in a military coup, just how far they will go remains to be seen.
After this morning's violence, workers in all the state unions, which cover mainly utilities and transport, came out on strike in sympathy with the protesters.
They plan to use the national grid to black out and deprive water from the homes of politicians and police leaders responsible for police violence they claim was used in an attack on the protesters at Government House.
Last night's violence was prompted after supporters of the Democratic Alliance Against Dictatorship, a pro-Samak, pro-Thaksin group, led by a man called Shinawatra Pabunchart moved on protesters at Government House.
He said today: 'More of our supporters are coming. We will take back Government House.'
Just how orchestrated it was remains unclear. But democrats say Mr Samak predicted the violence two days ago and it gave the prime minister an excuse to bring in the army.
Thousands of British tourists are still struggling to get home from holiday destinations in the south.
The Thai Airways Union, which is coming out in sympathy with the strikers, said it would do its best to help foreigners caught up in the troubles.
Meanwhile, the Foreign Office has advised caution amid fears of further violence in Bangkok and warned against all but essential travel through the southern provinces of Pattani, Yala, Narathiwat and Songkhla due to the risk of bombings and shootings.
Tourists should also check with their airline before they travel.
Thailand is one of the most popular places for British tourists with around 860,000 visitors from the UK last year. Recently it been wracked by internal conflict.
A Foreign Office spokesman said: 'Major demonstrations are taking place in central Bangkok.
'There have been outbreaks of violence between the police and protesters, including some use of tear gas.
'There is the possibility of further violent clashes. You should exercise caution, avoiding any demonstrations or large gatherings of people. You should also keep yourself informed of developments, including by regularly checking this advice and the media.
'We advise against all but essential travel to, or through, the far southern provinces of Pattani, Yala, Narathiwat and Songkhla. There continue to be frequent attacks, including bombing and shooting, due to insurgency and civil unrest in these areas.'
