The military takeover in Thailand has drawn swift international condemnation, with the United States saying it was reviewing its military aid and other dealings with its closest ally in Southeast Asia.
Thailand's army chief, General Prayuth Chan-ocha, seized control of the government two days after he declared martial law, saying the military had to restore order and push through reforms after six months of turmoil.
The military declared a curfew from 10pm until 5am, suspended the constitution and detained some politicians. Rival protest camps were ordered to disperse.
Ousted Prime Minister Yingluck Shinawatra, members of her cabinet, and other influential individuals from both sides of the political divide - in total more than 100 people - were told to report to the military in central Bangkok at 10am (0300 GMT) on Friday.
"There is no justification for this military coup," US Secretary of State John Kerry said in a statement.
A proposed political amnesty bill sparked mass protests late 2013. Critics feared it would allow ousted PM Thaksin Shinawatra, convicted of corruption, to return.
His sister Yingluck, then PM, called early elections. The Constitutional Court declared results invalid due to opposition disruption.
On May 7, the Constitutional Court ruled that Yingluck had to step down for abuse of power. Parts of her government stayed on in a caretaker capacity.
"This act will have negative implications for the US-Thai relationship, especially for our relationship with the Thai military. We are reviewing our military and other assistance and engagements, consistent with US law."
European and Asian nations expressed concern over the coup, with Germany, France and Britain issuing statements of condemnation, Japan's foreign minister calling it "regrettable" and Singapore urging all sides to avoid violence.
UN calls for dialogue
Kerry said he was concerned by reports that senior political leaders had been detained and called for their release. He urged the "immediate" restoration of civilian government and the lifting of curbs on the media.
UN Secretary-General Ban Ki-moon said he was "seriously concerned" and appealed "for a prompt return to constitutional, civilian, democratic rule and an all-inclusive dialogue that will pave the way for long-term peace and prosperity."
Under US law, with limited exceptions, no US foreign aid may flow to "any country whose duly elected head of government is deposed by military coup d'etat or decree".
The Pentagon said it was reviewing its military cooperation, including an ongoing joint exercise in Thailand involving about 700 US Marines and sailors.
State Department spokeswoman Jen Psaki said that as much as about $10m in annual bilateral aid could be cut.
The capital, Bangkok, was calm and activity appeared to be relatively normal early on Friday, although the military has ordered all schools and universities to stay closed.
"There's a little bit more military presence but we're not looking at a situation with tanks rolling onto the streets," Al Jazeera's Scott Heidler, reporting from Bangkok, said.
Regular television schedules were suspended with all stations running the same news programme, featuring content from Channel 5, the army's own channel.
It showed pictures of the areas, now cleared, that had been taken over in and around Bangkok by various political groups since anti-government protests flared up last November.
Thursday's coup announcement came after a second day of negotiations between the army, political groups, senators and members of the election commission failed to resolve the country's political crisis.
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"It is necessary for the Peace and Order Maintaining Command - which includes army, navy, armed forces and police - to take control of governing the country," Chan Ocha said.
It is the country's 12th coup since the absolute monarchy ended in 1932. There had been 19 attempted coups as well in the period.
The leader of the so-called Red Shirts, which supports the now-deposed cabinet, said the group would continue its rally on the outskirts of Bangkok despite the military seizing control of the government and telling all protest groups to disperse.
"We will not go anywhere. Don't panic because we expected this," Red Shirt leader Jatuporn Prompan told supporters.