Martial law is now in place throughout Thailand, where months of violent anti-government protests have caused political paralysis and hurt the economy. The military says the imposition of martial law is not a coup, but a bid to restore order. Here's a look at the key players in Thailand's political crisis:
King Bhumibol Adulyadej
King Bhumibol Adulyadej, 86, has intervened in past conflicts but has kept silent in this prolonged stand-off. While he has the moral authority to intervene, he has stated previously his reluctance to use those powers. He is also in poor health, making it hard for him to be the final arbiter even if he wanted to.
It is a measure of the reverence Thais hold for the King that both camps in this bitter conflict claim to be loyal subjects. Ironically, anxieties about the looming royal succession add to the intensity of their power struggle.
General Prayuth Chan-ocha
The blunt-speaking, 60-year-old army chief is just months away from retirement. Now that he has imposed martial law, he has a huge task on his hands trying to end Thailand's debilitating conflict.
He has to be very careful to be seen as fair to both camps or risk matters escalating out of control.
Part of the army's elite Burapha Phayak or "eastern tigers'' clique, the general is seen as close to Queen Sirikit and a natural defender of the anti-Thaksin establishment. But analysts have credited him for his restraint despite calls in the past months for the military to oust the government and take over the running of the country.
The 64-year-old former deputy prime minister and senior member of the opposition Democrat Party has been leading the protests against the Puea Thai government since late last year.
As the head of the anti-government People's Democratic Reform Committee, he has declared more than 10 "final battles", after which he would surrender to the police to face charges against him. This includes murder charges for his role overseeing a crackdown on "Red Shirt" protesters in Bangkok in 2010.
The firebrand speaker was made leader of the pro-government United Front for Democracy Against Dictatorship - better known as the 'Red Shirts' - in early March. Since then, the group has mobilised thousands of people to support the Yingluck government in the capital.
Prior to the imposition of martial law, the 48-year-old activist had threatened to escalate the fight if an interim prime minister was appointed. How the Red Shirts react in the days to come will depend a lot on his response to martial law.
The 46-year-old former business executive was made Prime Minister after Puea Thai party won a landslide victory in the 2011 elections. She could not, however, shake off persistent accusations that she was just a puppet of her brother Thaksin Shinawatra, a controversial telecommunications tycoon turned premier who was ousted in a military coup in 2006.
She has largely kept a low profile since May 7, when she was expelled by the Constitutional Court, alongside nine other caretaker ministers, over a questionable transfer of a senior official.
Since 2008, Thaksin has lived abroad to evade a corruption-related jail sentence, which he says is politically motivated.
He tweeted on Tuesday: "The declaration of martial law is expected.... however I hope no party will violate human rights and further destroy democracy."