BANGKOK — Amid monsoon downpours, pro-democracy demonstrators sang and danced at a police barricade in Bangkok on Tuesday, marking the fourth anniversary of an army coup that again plunged Thailand into military rule.
The festive atmosphere, though, was undercut by police broadcasts over loudspeakers warning that the protesters, some of whom had wished to remain anonymous, had been identified through photographs and video footage. Security provisions imposed by the ruling junta have made any political gathering of more than four people illegal. Anyone participating in the demonstration could be considered to have broken the law.
“Many young people are scared to speak out because they are worried about their future,” said Thanawat Prommajak, a youth activist whose voice had grown hoarse from yelling into a microphone. “The military junta wants to crush us.”
Most of the protesters, who were calling for elections to be held this year, were contained at Thammasat University in Bangkok’s old quarter, the site of a massacre of student activists four decades ago. But a breakaway group of dozens tried to march toward Government House, the seat of in Thailand’s executive power. The police herded the organizers of that protest cell into vans and shoved away members of the media.
Shortly afterward, the authorities detained the leaders of the main rally at Thammasat University, which attracted several hundred people, far short of the thousands the democracy movement had hoped.
Throughout the day, the protesters flashed the three-finger salute from the Hunger Games films that is meant to signal a silent defiance of authoritarian governance. Members of the military junta have called for a ban on the gesture, and at previous rallies the police detained protesters who were seen using it.
“I am showing that I will never give in to the military,” said Sirawith Seritiwat, a protest leader who was wearing a T-shirt with the Hunger Games salute on it. “Even after four years, after being arrested, after being intimidated, I will never give in to a dictatorship.”
Mr. Sirawith, who briefly fainted after making speeches in the heat, was later taken away by the police.
After seizing power in 2014, Thailand’s ruling junta, which calls itself the National Council for Peace and Order, vowed that it would promptly return power to a civilian administration. But the military government, led by Prime Minister Prayuth Chan-ocha, has repeatedly delayed elections. The latest timeline has voting scheduled for February 2019, but many Thais have little confidence they will take place then.
“We don’t believe the military government will hold elections next year because all they do is lie to us,” said Nopakrai Jaidee, who had camped out overnight at Thammasat to ensure he would be able to join the demonstration.
The 2014 coup was the second military putsch aimed at unseating a political force loyal to Thaksin Shinawatra, a former telecommunications magnate who served as prime minister from 2001 to 2006. Mr. Thaksin has been praised for standing up to Thailand’s entrenched political establishment but criticized for the corruption and abuse of power that flourished during his administration.
His tenure was cut short by army tanks in 2006. The government of his sister, Yingluck Shinawatra, was ousted by the 2014 coup. Every election in Thailand this century has brought to power parties loyal to Mr. Thaksin.
Thailand, which has weathered 12 successful coups since absolute monarchy was abolished in 1932, has been politically polarized for more than 15 years. At first, the divisions, in their broadest terms, set a rural populace against the urban elite. But as Thailand’s military leaders have lingered, even members of Bangkok’s ruling class have urged a return to democratic governance.
The junta’s response has been severe. Those who criticize the military government have been packed off to “attitude-adjustment camps” run by the army. Just before Tuesday’s protest, eight members of the Pheu Thai Party, which is affiliated with Mr. Thaksin, were charged with sedition or with flouting a ban on political activity.
Mr. Prayuth, who was army leader when the coup plotters struck, was welcomed by President Trump to the White House in October.
“Thailand is nowhere near what the ruling junta promised would be a rights-respecting democratic country,” said Sunai Phasuk, a senior researcher on Thailand for Human Rights Watch. “Now more than ever, pressure from the international community is urgently needed to help Thai people.”
This month, Defense Minister Prawit Wongsuwan indicated that political parties would not be able to resume full activities next month, as had previously been suggested. Mr. Prawit, who is second in command in the junta, has been the target of ridicule by the opposition for the collection of luxury watches he wears.
The timepieces, more than two dozen by one count, were not declared as assets to the nation’s anti-corruption commission, as is required for politicians in Thailand. Mr. Prawit says the watches were lent by friends.
“The government is filled with military men who hold full authority in their hands,” said Mr. Thanawat, the youth activist. “They will use that authority to their benefit to keep themselves in power. That is their goal.”
From the police station where he was taken after the rally was dissolved, Rangsiman Rome, a student leader of the rally on Tuesday’, sent a WhatsApp message: “My feeling is sad,” he wrote, “because a lot of people got hurt and arrested.”
Follow Hannah Beech on Twitter: @hkbeech.