Bangkok, Thailand (BBN)-The US has led widespread international criticism of a military takeover in Thailand as the South-East Asian nation spent its first night under curfew.

US Secretary of State John Kerry said there was "no justification", and $10m in bilateral aid could be suspended, reports BBC.

France and Germany condemned the coup, with the UN expressing serious concern.

The army on Thursday suspended the constitution, banned gatherings and detained politicians, saying order was needed after months of turmoil.

The military had declared martial law on Tuesday. Two days later, it gathered political leaders together in Bangkok for talks on the crisis.

However, army chief Gen Prayuth Chan-ocha then went on TV to announce the coup.

Several key figures at the talks, including opposition protest leader Suthep Thaugsuban and pro-government protest leader Jatuporn Prompan, were detained.

Acting PM Niwatthamrong Boonsongphaisan was not at the talks and his whereabouts are unclear.

For many of the opposition PDRC's supporters, a coup is the end result they had been hoping for.

But questions remain. Did Gen Prayuth really expect to achieve success in talks in two short meetings? Or was it his always his intention to make a token nod towards negotiations before stepping in?

Could the talks really have been a ruse to get all the key leaders in one place before detaining them?

There has been some suggestion that elements within the Thai army may have forced his hand.

The rush from martial law to full-blown coup has left many here shaking and scratching their heads.

His adviser Paradorn Pattanathabutr told the Associated Press news agency: "The rest of us who are outside are still fine and in safe places."

Niwatthamrong and all his cabinet ministers, along with two former PMs – Yingluck and Somchai Wongsawat – were ordered to report to the military on Friday morning.

The military later expanded that summons to include more than 100 leading figures from both political camps.

Thailand has now ended its first night under curfew.

'WE WEREN'T SCARED'

The UN responded to the coup by expressing "serious concern", with Secretary General Ban Ki-moon urging a "prompt return to constitutional, civilian, democratic rule".

Kerry said there was "no justification for this military coup".

He said: "While we value our long friendship with the Thai people, this act will have negative implications for the US-Thai relationship, especially for our relationship with the Thai military."

Up to $10m in bilateral assistance could be suspended.

The UK urged "all sides to put aside their differences, and adhere to the values of democracy and the rule of law".

The French president and German foreign minister condemned the coup, while Japan's foreign ministry termed it "regrettable".

A spokesperson for EU foreign policy chief Catherine Ashton said it was important to hold "credible and inclusive elections as soon as feasible".

Thailand's Association of South-East Asian Nations (Asean) partner Singapore expressed "grave concern".

Bangkok remained largely peaceful after the coup.

One key flashpoint was the pro-government "red shirt" camp on Bangkok's western outskirts but protesters packed up without violence.

There was heavy traffic on the streets as the curfew deadline loomed but they were largely deserted overnight.

Television has been restricted to broadcasts by the military. The BBC, CNN and other channels are off air.

KEY COUP CONDITIONS

The army has staged at least 12 coups since the end of the absolute monarchy in 1932.

Thailand has faced a power struggle since Yingluck's brother, Thaksin Shinawatra, was ousted by the military as PM in 2006.

Thaksin and Yingluck have strong support in rural areas. They are opposed by many in the middle class and urban elite.

The latest unrest began in the Thai capital late last year, when anti-government protesters embarked on a campaign to oust Yingluck's government.

A court ordered her removal for alleged abuse of power this month.

BBN/ANS/AD-23May14-10:30am (BST)