Shortly before the announcement was made, armed soldiers in military vehicles surrounded the army facility where the politicians were meeting, apparently to block those inside from leaving.
Many of the country's highest-profile figures were summoned for the meeting. They included the acting prime minister - who sent four Cabinet ministers in his place - and anti-government protest leader Suthep Thaugsuban, as well as Suthep's rival from the pro-government Red Shirt group, Jatuporn Prompan. Suthep and Jatuporn were escorted out of the meeting by soldiers and detained.
A government official, Paradorn Pattanathabutr, contacted shortly after the announcement said the four ministers attending the meeting were still being held by the military.
"The rest of us who are outside are still fine and in the safe places. However, the situation is very worrying. We have to monitor it closely and don't know what else can happen," he said.
Thailand, an economic hub for Southeast Asia whose turquoise waters and idyllic beaches are a world tourist destination, has been gripped by off-and-on political turmoil since 2006, when former Prime Minister Thaksin Shinawatra was toppled by a military coup after being accused of corruption, abuse of power and disrespect for Thailand's king.
His overthrow triggered a power struggle that in broad terms pits Thaksin's supporters among a rural majority against a conservative establishment in Bangkok.
The latest round of unrest started in November, when demonstrators took to the streets to try to oust then-Prime Minister Yingluck Shinawatra, Thaksin's sister. She dissolved the lower house of Parliament in December in a bid to ease the crisis, and later led a weakened caretaker government.
Since November, 28 people have been killed and hundreds injured, mostly in drive-by shootings and grenade attacks on protest sites.
Earlier this month, the Constitutional Court ousted Yingluck for abuse of power. But the move, which left the ruling party in charge, did little to resolve the conflict.
The army action followed threats by anti-government protesters to intensify their campaign to oust the ruling party, and an attack last week on protesters that killed three people and injured over 20.
Prayuth invoked the military's expanded powers Tuesday and issued more than a dozen edicts that included broad powers of censorship over the media, the Internet and vaguely defined threats to prosecute opponents.
The military had insisted it was not seizing power, but said it was acting to prevent violence and restore stability in the deeply divided country. But he provided little clarity on a path forward, amid speculation both at home and abroad that the declaration of martial law was a prelude to a military coup.
