In his official announcement that the coup had taken place, army chief General Prayuth Chan-ocha said: "In order for the situation to return to normal quickly and for society to love and be at peace again ... and to reform the structure of the political, economic and social structure, the military needs to take control of power." Soldiers stand guard during a coup at the Army Club where Thailand's army chief held a meeting with all rival factions in Bangkok. Credit:Reuters After this announcement, the army suspended the constitution and banned gatherings of more than five people. Although the 2007 constitution has been suspended, the Senate upper house will continue to function. The army named 17 people on television who should report to the army. First on the list was deposed Prime Minister Niwattumrong Boonsongpaisan. An army spokesman said people should remain calm and continue to go about their normal activities.

"We will provide security for foreigners," he said. Thai and foreign journalists watch and listen to the announcement of the coup on television at the Army Club's press centre in Bangkok. Credit:AP The curfew will affect tens of thousands of tourists in resort areas like Phuket, Chiang Mai and Pattaya. It is also expected to create chaos for travellers arriving into and leaving the country and will affect dozens of flights, because passengers are prohibited from travelling after 10pm. A spokesperson for the Department of Foreign Affairs and Trade urged all Australians travelling to Thailand, or already in Thailand, to continue to exercise a high degree of caution and to pay close attention to their personal security. Thailand's army chief General Prayuth Chan-ocha (left) leaves after meeting with anti-government and pro-government leaders. Credit:AFP

"Suvarnabhumi International Airport and Don Mueang Airport in Bangkok are operating normally," the spokesperson said. "Authorities have advised that the curfew will not apply if travelling to or from an airport. Travellers should have passports and tickets with them when travelling to and from the airport. Thailand’s military has launched a coup three days after insisting its troops would not stage a full takeover. Credit:Apichart Weerawong "Australians should follow the instructions of local authorities and avoid all demonstrations, protest sites, political events and large-scale public gatherings. Australians travelling to Thailand should visit www.smartraveller.gov.au, familiarise themselves with the travel advice, subscribe to receive regular updates and register their travel plans." Embassies around the world advised their citizens in Thailand to exercise extreme caution.

Many Thais will not know about the curfew because Thai television and radio stations have been taken off the air, although the internet and social media sites like Twitter are still operating. International television stations like the ABC's Australia Network, CCN and BBC were taken off at least one cable channel provider. The Cartoon channel was even taken off air. Troops have been deployed in large numbers across Bangkok, where major shopping centres have closed early and restaurants, bars and other businesses are shuttered. They entered television stations that were not already closed and the stations that remain open began playing soothing music. Troops were also in newspaper offices. Workers rushed to public transport to get home before the 10pm curfew. Roads were also choked with people going home. Troops manned dozens of check points at major intersections.

As commanders appeared on television about 5pm Bangkok time (8pm AEST) to declare they had taken over, the leaders of both rival political parties in Thailand were taken away in a vans amid dramatic scenes at the Army Club in central Bangkok, where talks were being held to try to find a resolution to six months of sometimes violent unrest. A military source said the leaders were told "we will keep you together until you understand and love each other". Formally announcing the coup on television, General Prayuth said martial law had moved to a full-blown coup, to quell political violence and "ensure fairness for every side". ''To restore peace back to the country in a short time and to reform the country's politics, economy and society, the Thai military, army, navy, air force and police have seized power from May 22 onward,'' General Prayuth said. "I ask the people to remain calm and carry on with their business as usual."

Not long after the announcement of the coup, a burst of gunfire was heard on Uttayan Road, where the pro-government Red Shirt protesters have been camped. Earlier, soldiers who arrived in trucks at a Red Shirt campsite on the western outskirts of Bangkok said they would take people home. They arrested key Red Shirt leaders who were on stage at their rally site. Reports said soldiers had asked Red Shirt protesters to stay put and lie face down on the ground. A photo shared via Twitter showed Red Shirt guards and protesters ducking down as soldiers moved in on the protest. The Red Shirt group posted on Twitter: "Now it is a coup - stand-by for retaliation." At least five top Democrat opposition party officials were in detention, including leader Abhisit Vejjajiva. The Democrat party boycotted elections in February that were later annulled by the Constitution Court.

Soldiers surrounded the house of veteran politician and former Labor minister Chalerm Yumbumrung and detained him and two of his sons. The Red Shirt centre posted another message on Twitter saying "many of our co-leaders have been detained without whereabouts (known) - they are most likely detained at an army base." Interim Prime Minister Niwattumrong Boonsongpaisan learnt of the coup while at the Commerce Ministry. He had stayed away from the Army Club talks. Mr Niwattumrong said he then went to offices of the former ruling Pheu Thai party and then to an unknown location. Staff in the prime minister's office said they did not know where Mr Niwattamrong was, and the US embassy denied he had taken shelter there.

Unconfirmed reports said he had been arrested. Earlier on Thursday, Mr Niwattumrong insisted he would not resign and said his caretaker cabinet would remain in office until a new elected government was formed. The army declared that the coup commanders were operating through a body called the National Peacekeeping Committee. The coup is the 19th staged by the country's powerful armed forces since 1932. The takeover will enrage Red Shirt supporters of the caretaker government that wanted to push ahead with fresh elections.

Red Shirt leaders had vowed to rise up if the government that was elected in a landslide victory in 2011 was unconstitutionally deposed. The military's move is expected to be condemned by countries around the world, including Australia. The US will consider imposing sanctions on the military, a close ally. General Prayuth is expected to move swiftly to appoint a new government. A front-runner for the prime ministership is Kittipong Kittayarak, a former Permanent Secretary of the Justice Ministry. Dr Kitttipong has been involved in judicial reform in Thailand for more than a decade.

A graduate of Cornell Law School in the United States, he is on the board of Transparency International Thailand and has lectured at major Thai universities. Political analyst Thittinan Pongsudshirak said it was likely a new military-backed government would be installed within days. Loading "I am afraid over in the coming days and weeks there will be turmoil," he said. "Pro-government Red Shirts are likely to come out in large numbers."