Scores of ousted Thai government officials surrendered to the military, and soldiers broke up a demonstration in central Bangkok on Friday, as the army cemented its power the day after declaring a coup.
Former Prime Minister Yingluck Shinawatra arrived at a Royal Thai Army facility in a black Volkswagen van, flanked by bodyguards, ending speculation that she had fled Thailand or gone into hiding, according to local media reports.
Yingluck, who was forced from office by a court ruling two weeks before the coup, was the most prominent of the 155 people -- including former government officials, their aides and some prominent opponents -- ordered into military custody by the army chief, Gen. Prayuth Chan-ocha.
The army said Yingluck, who was detained at the Infantry 11 barracks, would be held for "no longer than a week."
The officials turned themselves in largely without incident. The military issued an announcement Friday barring those on the list from leaving the country without permission.
Thailand's coup, the 12th successful military takeover since the Southeast Asian nation abolished its absolute monarchy in 1932, has drawn widespread condemnation. The military has suspended the constitution, ordered a media blackout and so far has not set a timetable for restoring civilian rule.
Prayuth said the coup was necessary to restore stability to Thailand after six months of occasionally violent protests between supporters and opponents of Yingluck's government, which is linked to her controversial brother, the ousted former prime minister, Thaksin Shinawatra.
Most of Bangkok was calm, but a few hundred anti-coup demonstrators rallied around dusk Friday outside the Bangkok Arts and Culture Center despite a military order banning gatherings of more than five people. Some of the demonstrators were wearing white masks bearing the letter "X" to protest the media blackout; others carried anti-military signs.
Some of them began berating about 100 soldiers who were positioned nearby. As tensions escalated, more troops arrived and began to detain people. At least five people were arrested, although at least one was released an hour later. By nightfall, the military had cleared the area along a main thoroughfare.
Anti-coup groups protesting in central Bangkok organized the gathering via text message and Facebook. Analysts worry that the protests could escalate in the coming weeks and turn violent, as they did following a 1991 military coup.
A 56-year-old man who gave his name only as Tripop, an American citizen of Thai origin, said more protesters would gather in central Bangkok on Saturday.
"I don't know much about Thai politics because I live abroad, but I don't like coups, that's for certain," he said. "Only the red shirts come out and challenge the power of the military, nobody else."