BANGKOK (AP) -- The top general in Thailand's ruling junta warned people Sunday not to join anti-coup street protests, saying normal democratic principles cannot be applied at the time, as troops fanned out in central Bangkok to prevent rallies.
Gen. Prayuth Chan-ocha also defended the detentions of dozens of politicians and activists, most of them associated with the ousted government, with a spokesman quoting him as saying that the measure would not last more than a week and was allowed by law.
In a chilling move apparently aimed at neutralizing critics and potential opposition, the junta has also ordered dozens of outspoken activists, academics and journalists to surrender themselves to military authorities, including a prominent Thai reporter.
Pravit Rojanaphruk, an outspoken columnist for the English-language daily The Nation, tweeted that he was reporting to the junta: "On my way to see the new dictator of Thailand. Hopefully the last," he wrote.
The military, which is already holding most of the Cabinet ousted in a coup Thursday in secret locations, said it would keep former Prime Minister Yingluck Shinawatra and others in custody for up to a week to give them "time to think" and keep the country calm.
Starting Monday, those in detention who have arrest warrants or face criminal charges will be handed over for prosecution, said deputy military spokesman Col. Winthai Suvaree.
He also said that the general "urged every group of citizens to avoid joining the anti-coup protests because at the moment, the democratic principles cannot be executed normally."
In the three days since Thailand's first coup in eight years, the junta has faced scattered protests that came amid growing concern over its intentions. Troops were deployed in central Bangkok's central shopping district Sunday in a bid to stop any gatherings.
On Saturday, around 1,000 anti-coup protesters defied an army-imposed edict banning groups larger than five from gathering for political purposes. They were met by hundreds of soldiers, and the groups eventually dispersed.
Several demonstrators have been detained, and rights groups have expressed concern over the growing repression.
The military on Saturday dissolved the Senate -- the last functioning democratic institution left, and absorbed its legislative powers.
"Military rule has thrown Thailand's rights situation into a free fall," said Brad Adams, Asia director at Human Rights Watch. "The army is using draconian martial law powers to detain politicians, activists and journalists, to censor media, and to ban all public gatherings. This rolling crackdown needs to come to an end immediately."
More than 150 people have been held incommunicado, according to rights groups. Deputy army spokesman Col. Weerachon Sukondhapatipak said they were all being well-treated and the military's aim was to achieve a political compromise.
The junta summoned 35 more people, including politicians, political activists and, for the first time, outspoken academics and some journalists.
One of those on the list, Kyoto University professor of Southeast Asian studies Pavin Chachavalpongpun, said by telephone from Japan that he would not turn himself in. He said the summons meant the junta felt insecure.
"The military claiming to be a mediator in the Thai conflict, that is all just nonsense," said Pavin, who is frequently quoted by foreign media as an analyst. "This is not about paving the way for reform and democratization. We are really going back to the crudest form of authoritarianism."
The military also ordered banks to freeze the assets of two top politicians it had summoned but who remain in hiding, including the ousted education minister and the chief of the former ruling party.
Gen. Prayuth has justified the coup by saying the army had to act to avert violence and end half a year of political turmoil triggered by anti-government protests that killed 28 people and injured more than 800.
The intractable divide plaguing Thailand today is part of an increasingly precarious power struggle between an elite, conservative minority backed by powerful businessmen and staunch royalists based in Bangkok and the south that can no longer win elections, and the political machine of exiled former Prime Minister Thaksin Shinawatra and his supporters in the rural north who backed him because of populist policies such as virtually free health care.
The army deposed Thaksin in a 2006 coup. And on Friday, it detained his sister, Yingluck, who was forced from office earlier this month by a controversial court verdict for abuse of power, which she denies.
The ruling party, which rose to power in a landslide election in 2011 that was deemed fair, had insisted for months that Thailand's fragile democracy was under attack from protesters, the courts and, finally, the army which together had rendered it powerless.