A protester is detained by Thai soldiers during an anti-coup demonstration at the Victory Monument in Bangkok, Thailand, Saturday, May 24, 2014. Thailand's coup leaders said Saturday that they would keep former Prime Minister Yingluck Shinawatra, Cabinet members and anti-government protest leaders detained for up to a week to give them "time to think" and to keep the country calm. They also summoned outspoken academics to report to the junta. (AP Photo/Wason Wanichakorn)

BANGKOK (AP) -- In a chilling move apparently aimed at neutralizing critics and potential opposition, Thailand's new army junta ordered dozens of outspoken activists, academics and journalists to surrender themselves to military authorities.

The junta, which is already holding most of the government it ousted in a coup Thursday in secret locations against their will, 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.

Two days after the army seized power in the nation's first coup in eight years, it also faced scattered protests that came amid growing concern over the junta's intentions. Also Saturday, the military 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, mostly politicians associated with the deposed government, have been detained 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.

Weerachon said all those held have had their cellphones confiscated because "we don't want them communicating with other people. We want them to be themselves and think on their own," he said, adding that they need to "calm down and have time to think."

"We don't intend to limit their freedom — it's to relieve the pressure," he said.

The weeklong detention is allowed by law, said deputy military spokesman Col. Winthai Suvaree, quoting army chief and junta leader Gen. Prayuth Chan-ocha. Starting Monday, those in detention who have arrest warrants or face criminal charges will be handed over for prosecution, he said.

In a military order broadcast Saturday, 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."

Saturday evening, the junta broadcast its sixth official order, for a single journalist: Pravit Rojanaphruk, an outspoken columnist for the English-language daily The Nation, who was summoned to report to the army at 10 a.m. Sunday. Pravit was defiant, tweeting that "the more they exercise their illegitimate power the more illegitimate they become."

The junta 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.

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