Army Chief Gen. Prayuth Chan-ocha staged a coup on Thursday (May 22), telling the public "not to panic," locking up top political leaders, suspending the constitution, and sparking fears
of a backlash by angry Thais demanding a return to elections and democracy.

Thailand is a vital non-NATO treaty ally of Washington, and U.S. law requires cancellation of some military aid and other assistance when a country's military overthrows an elected government.

Grim-faced Gen. Prayuth said in a nationwide TV broadcast he seized power because "the violence in Bangkok and many parts of the country that resulted in loss of innocent lives and property, was likely to escalate."

He was referring to the past six months of blockades in Bangkok, led by pro-military, anti-election protesters who hoped to topple the elected government.

Sporadic clashes in Bangkok killed at least 28 people on both sides since November.

"We ask the public not to panic, and to carry on their lives normally," Gen. Prayuth said, flanked by four men representing the U.S.-trained air force, navy, army and police, with the general as
their self-appointed leader.

"Our co-leaders -- including Jatuporn, Nattawut, Thida, Veerakarn, and Korkeaw -- have been detained," tweeted the pro-election Red Shirts' office, minutes after Gen. Prayuth announced his coup.

Those pro-democracy Red Shirt leaders represent many within the country's majority of voters who brought the doomed civilian government into power.

Their enemy, anti-government protest leader Suthep Thaugsuban, supported the military amid hopes they would install an appointed regime of technocrats instead of politicians, but Mr. Suthep was also detained.

Mr. Suthep's colleague, former Prime Minister Abhisit Vejjajiva, was also captured.

All of them had been lured to meet Gen. Prayuth on Thursday (May 22) at the Army Club in Bangkok for a second day of talks at that venue, to end six months of confrontations in Bangkok's streets.

It was unclear what was said during those talks, but Gen. Prayuth seized power while they were behind closed doors.

He immediately put the politicians into black vans along with soldiers, and transported them to the army base next door, where they were held.

The military then ordered Acting Prime Minister Niwatthamrong Boonsongpaisan to turn himself in "to keep peace and order."

A ban against "political gatherings" of more than five people was also announced.

"Anyone who violates the ban will be subject to a one-year jail term, 10,000 baht ($330) fine, or both," a TV broadcast by the new military junta said.

"In order to run the country smoothly, [the military] suspended the constitution of 2007, except for the chapter on the monarchy," the military said in a later TV broadcast.

The military helped write that 2007 constitution after their 2006 coup, to lessen the power of elected politicians, and strengthen appointed courts and other unelected institutions.

Thailand has experienced 18 coups and attempted putsches since 1932, creating a pattern of military dictatorships interspersed by brief democratically elected governments.

When Gen. Prayuth announced his coup, thousands of Red Shirts were camped on Bangkok's outskirts, threatening to act if the military overthrew the elected government.

Troops immediately moved into that rally and dispersed the Reds.

In a dramatic capture, a soldier armed with an assault rifle and wearing a black balaclava to disguise his face, helped to arrest at least one surprised Red Shirt leader onstage, while a beret-wearing officer used the rally's microphone to tell people to go home.

Gen. Prayuth had clashed with the Red Shirts in 2010 when Reds demanded elections during their insurrection in Bangkok's streets.

The army, backed by armored personnel carriers, crushed the Reds, with a total death toll after nine weeks of more than 90 people, most of them civilian Reds, but also some soldiers and journalists.

Earlier, in 2006, Gen. Prayuth participated in a bloodless coup against the popularly elected government of then prime minister Thaksin Shinawatra.

That coup polarized the country and fueled the political chaos which continues to convulse this prosperous Buddhist-majority country.

Gen. Prayuth's military has also not been successful on the battlefield against seemingly unstoppable Islamist insurgents who are fighting for a separate ethnic Malay homeland in the south, where more than 4,500 people on all sides have died since 2004.

Meanwhile, the military junta's announcements on Thursday (May 22) included a nationwide curfew from 10 p.m. to 5 a.m., which may remain for several nights.

In addition to lessening any attacks in darkness, the curfew will destroy much of Thailand's lucrative tourism industry because travelers and residents flock to bars, clubs, dance halls, massage parlors, night street markets and other lively entertainment.

International air travelers were advised they would be permitted to go to and from the country's airports during curfew hours, though their vehicles could be stopped at roadblocks to confirm their identity and route.

A few hours after the coup, the TV channels of CNN and the BBC were blocked, replaced by military-themed songs, photos of weapons, insignias of the armed forces and police, and an occasional update by a military spokesman.

Troops also entered some Thai newspaper offices and stood guard, journalists said.

When "a coup has taken place in Thailand, the United States will be required to end much of its aid," a Center for Strategic International Studies (CSIS) analysis said.

"Following the last military coup in 2006 which ousted the prime minister Thaksin Shinawatra, the United States froze military aid to Thailand including funds for military sales, training officers under the International Military Education and Training program, and funding for peacekeeping and counter-terrorism training," it said.

"The 1961 Foreign Assistance Act says the United States 'restricts assistance to the government of any country whose duly elected head of government is deposed by military coup or decree'," said the Singapore-based CSIS report on Tuesday (May 20) by Ernest Z. Bower and Murray Hiebert.

Gen. Prayuth had declared martial law on Tuesday (May 20) and immediately unleashed harsh restrictions against the media.

All text, photos, TV and radio broadcasts, plus satellite and other online telecommunications, are "prohibited" if they report "distorted" information which "could cause social division and unrest," or "widespread fear," Gen. Prayuth's self-created Peace and Order Maintaining Command declared.

They must immediately report any "announcements from the Royal Thai Army" when told to do so.

More than a dozen private TV broadcasters and scores of small radio stations were quickly shut, but mainstream media had been largely left to self-censor its content.

In response, Thais and foreigners -- including American, British and other expats resident in Thailand -- blasted Gen. Prayuth amid widespread expectations that he will not allow fresh nationwide elections any time soon.

"I do not recall having voted for General Prayuth, nor handing him my consent to rule over me and the rest of us like a dictator," wrote Pravit Rojanaphruk, a respected Thai analyst.

"Martial law as a drug to suppress political diarrhea won't solve anything in the long run," Mr. Pravit said, before the coup.

He also worriedly tweeted to BBC's correspondent Jonah Fisher:  "If I'm no longer tweeting then let it be known that I am being censored or literally removed under martial law. #freethailand".

Some activist Thai lawyers had questioned the legality of Gen.
Prayuth's martial law.

Prachathai, a popular website, posted a report by Thaweeporn Kummetha which said, "Army Chief Prayuth Chan-ocha decided to intervene by illegally declaring the Martial Law."

According to Prachathai's website, George Soros's Open Society Foundation donated more than $200,000 to Prachathai since 2004, while the Rockefeller Foundation and other international groups also funded the news site.

"Our foreign donors" did not "interfere with our reporting," Prachathai said.

Websites which were targeted under martial law displayed a rerouted online address which said: "58.97.5.29/announce/martial_law.html" and a statement that it has been blocked.

In response, geeks began deconstructing the military's online censorship.

The army set up an "Online Subcommittee, with direct access to ISPs," tweeted @thainetizen, referring to Internet Service Providers which help link Thailand to the rest of the world.

"Websites taken down in 1 hour after an order" from the military, the tweet warned.

"Thai media banned from carrying interviews with anyone who might 'confuse society.'  I've fallen into a Kafka/Orwell world and can't get up," Ezra Kyrill Erker tweeted.

"Today I'm going to enjoy some Martial Law," tweeted Lucky Erawan.