Police in Thailand fired tear gas to disperse thousands of anti-government protesters in Bangkok on Tuesday, injuring dozens of people.
Hospital officials said at least 50 people were injured, three seriously, as police intervened in the dawn protest in front of parliament.
Television footage showed police firing gas canisters, and clouds of white smoke on the road where the protesters had erected barbed wire and tyre barricades since late Monday.
The clashes came just hours before new Prime Minister Somchai Wongsawat was to deliver a key policy statement.
The protesters say he is a proxy for former Prime Minister Thaksin Shinawatra, and want the government to resign.
"It was absolutely necessary for police to use tear gas to break up the crowd," Major General Anan Srihiran told Reuters.
"We only wanted to open up a road for the cabinet to enter parliament. We will not do anything else to the protesters for the rest of the day."
Protesters from the People's Alliance for Democracy and their supporters have waged a nearly four-month campaign to unseat the government.
They have occupied the prime minister's offices at Government House since late August, forcing Mr Somchai to run the country from Bangkok's little used Don Muang airport.
The protesters want to replace one-man, one-vote with a system that has some representatives chosen by professions and social groups.