Bangkok (AsiaNews) – Thailand's coup d'etat "has succeeded in the name of king and constitution" and the military who pulled it off "will return power to the people as soon as possible through a council that will elect an ad interim government which will call new proper people's elections". This was announced at 2pm [local time] by the leaders of the Thai armed forces during an encounter with the accredited diplomatic corps in Bangkok.

Speaking in front of the photos of the king and queen – the only Thai authorities who are loved and respected by all the population – the generals added that for the moment, "martial law is in force and unauthorised mass gatherings and the dissemination of critical news are therefore prohibited." The bath [national currency] has crashed and tourism has declined although travel agencies have not declared Thailand to be an off limits country.

The coup leader, General Sonthi Boonyaratglin, says the military needed to seize power in order "to unite the nation after months of political turmoil". The general said: "All political organs have been terminated. We agreed that the caretaker prime minister has caused an unprecedented rift in society, widespread corruption, nepotism, and interfered in independent agencies, crippling them so they cannot function."

He added:  "The council has no intention to rule but to return power to the people as soon as possible." At the moment, soldiers patrolling Bangkok bear flowers on their guns and yellow ribbons [the colour of peace for Buddhists] are tied around the barrels, to show they have no intention of using violence against the crowds.

Army officials say the deputy prime minister, Chidchai Vanasathidya, the secretary to the Prime Minister's office, Prommin Lertsuridej and Thaksin's brother-in-law, Somchai Wongsawat, who is permanent secretary of the Justice Ministry, have been detained.

Meanwhile, the premier, who was in New York, attending a United Nations meeting, said "the coup cannot succeed" and that the government "still has control of the country in hand". His spokesman however added that the prime minister "has not yet decided whether to return to Thailand."

Brad Adams, Asia director for Human Rights Watch [HRW, an international organization working for respect for human rights worldwide] urged the military junta to restore basic civil liberties. He said: "Thailand needs to solve its problems through the rule of law and the people exercising their right to choose their own leaders."

"The return of tanks to the streets of Bangkok is clear evidence that the rights of all Thais are in jeopardy," Mr Adams said. "So, too, is Thailand's position in the region as a leading democracy with a strong civil society."

Adams added: "Thaksin's rule had seriously eroded respect for human rights in Thailand, but suspending basic rights under the constitution is not the answer."

Yesterday's was the first military insurrection in the country after 15 years of relative calm. After dozens of coups, in 1992, the military interrupted political turmoil with the fall of the last military regime that had forced them to massacre pro-democracy activists. The country reinforced its democratic system thanks to the Asian financial crisis of 1997 – 1998: to overcome it and to survive, MPs adopted a new, more democratic constitution, with the blessing of the sovereign.

The current political crisis was born from strong opposition against the premier: on 23 January 2006, a group of middle class activists launched a series of anti-government protests against the sale by the Thaksin family of shares held in Shin Corp – a telecommunications giant set up by the prime minister before he entered politics – to Temasek, a Singapore government holding. The premier netted 1.6 billion euros, tax exempt, and the country's middle class was infuriated.

The opposition accused him of using his political position to obtain "enormous advantages" from this sale and for having included shares of state companies in the deal, which he later sought to privatize to cover up the new management.

The problem has wider ramifications: a good deal of the national economy, which rests upon industry, is dependent on government funds; when these are exhausted,  many firms will be obliged to sack personnel to cut back on costs. The upshot is an economic crisis hitting the urban middle classes.

In a bid to diffuse the crisis, the premier – elected for the first time in 2001 and re-elected triumphantly in 2005 – dissolved parliament on 24 February and called a new election on 2 April, which the opposition decided to boycott.

The result of the polls handed over a relative majority to Thai Rak Thai, the party of the controversial premier but this, the only one on the lists because of the boycott, was beaten by the people's protest vote, expressed thanks to the "no vote" box on the voting sheet.

Two by-elections held later did not manage to fill the 40 seats that remained empty after the first consultation. The administrative High Court decided on 28 April to annul the third round of by-elections that should have been held the following day to assign the 14 still vacant seats.

The decisive intervention by the court had been requested on 26 April by the Thai monarch King Bhumibol Adulyadej, who had rejected calls to form a new government himself. In a rare public address, he said: "A parliament without opposition would have been anti-democratic."

Thaksin opposed the request to the courts to intervene in a move held to be the final "affront" for the people: accused of lacking in respect for the king, the premier lost the backing of the military.