Anti-government protesters climb a gate to enter parliament during a rally Wednesday in Bangkok. Protesters left the building after about 20 minutes, reports say. ((Kerek Wongsa/Reuters))

Thai Prime Minister Abhisit Vejjajiva has declared a state of emergency in Bangkok, handing control of law and order to the military after thousands of anti-government protestors stormed the Thai parliament on Wednesday morning.

Abhisit made the announcement on national television just hours after the so-called Red Shirt protesters smashed their way into the compound. Senior government officials inside fled through windows and scaled down ladders to escape. Others were evacuated by helicopter.

The government already had placed Bangkok under the strict Internal Security Act, but a state of emergency includes more sweeping powers. It gives the military authority to restore order and allows authorities to suspend certain civil liberties and ban public gatherings of more than five people.

Abhisit has also cancelled a planned trip to Vietnam on Thursday for a meeting of Southeast Asian leaders, the Reuters news agency reported. He was also supposed to attend a global nuclear summit in Washington next Monday, but scotched those plans earlier this week.

The so-called Red Shirt protesters are demanding that Abhisit dissolve parliament within 15 days and call new elections. He has offered to do so by the end of the year.

Demonstrators have been camped in Bangkok since March 12 and have ignored previous decrees for them to stop their protests. Abhisit has become the target of harsh criticism for failing to take strong measures to end the protests.

Anti-government protesters struggle with riot police outside parliament Wednesday. ((Chaiwat Subprasom/Reuters)) "The government has tried its best to enforce the law, but violations of the law have increased," Abhisit said in a televised statement that interrupted regular programming.

"Our main goal is to bring the country back to normal and make our law sacred once again." He did not spell out exactly how the emergency decree will be applied.

Red Shirt leaders responded to the emergency decree by telling protesters to stay put and wait for the military to arrive. They have called a major rally for Friday.

Veera Muksikapong, a protest leader speaking to a rally in Bangkok's central shopping district, directed a message to the army: "If you want to meet an army of nonviolent people, please come here. But I believe that ultimately the military will not listen to the government's order."

Abhisit's government is backed by the powerful military, but some have suggested the security forces are sympathetic to the protesters' cause and are reluctant to get tough on them.

On Tuesday, Thai authorities moved thousands of troops in riot gear to confront the demonstrators at their encampment in the middle of Bangkok's tourist and shopping district. The protesters had been banned from 11 main streets, but they surged past lines of soldiers and police to parade raucously down several roadways.

Thailand has been dealing with political turmoil since early 2006, when anti-Thaksin demonstrations began.