Thailand's military tightened its grip on power on Sunday as it moved to quell growing protests, saying anyone violating its orders would be tried in military court.
It also took its first steps to revitalize a battered economy, saying nearly a million farmers owned money under the previous government's failed rice-subsidy scheme would be paid within a month.
The military overthrew the government on Thursday after months of debilitating and at times violent confrontation between the populist government of Prime Minister Yingluck Shinawatra and the royalist establishment.
Critics say the coup will not end the conflict between the rival power networks: the Bangkok-based elite dominated by the military, old money families and the bureaucracy, and an upstart clique led by Yingluck's brother and former telecommunication mogul Thaksin Shinawatra. The Shinawatras draw much of their influence from the provinces.
The military has detained numerous people, including Yingluck and many of her ministers, party officials and supporters. Leaders of six months of anti-government protests against Yingluck have also been held. The military said they will be freed within a week.
The military has thrown out the constitution, censored the media, and dismissed the upper house Senate, Thailand's last functioning legislature. On Sunday, it said anyone accused of insulting the monarchy or violating its orders would face military court.
Power now lies in the hands of army chief General Prayuth Chan-ocha and his junta known as the National Council for Peace and Order, and their priorities appeared to be stamping out dissent and tending to the economy.
An army spokesman warned against protests and told the media to be careful in its reporting too.
"For those who use social media to provoke, please stop because it's not good for anyone," deputy army spokesman Winthai Suvaree said in a televised statement.
Despite the warnings, a small crowd of protesters, some holding handwritten signs such as "Anti the Coup" and "Get out Dictators," formed outside a central shopping center in the morning and grew through the day.
Hundreds of soldiers, most with riot shields, lined up to contain the crowd and there was some shouting and pushing and at least two people were detained, a Reuters reporter said.
By late afternoon about 1,000 people had gathered at the Victory Monument, a central city hub. A Reuters witness said trucks mounted with water cannon were on standby.
In his first public comments since the coup, Thaksin said on his Twitter feed he was saddened by what had happened and he called on the army to treat everyone fairly. Thaksin has lived in self-exile since a 2008 graft conviction and was himself ousted by the military in 2006.
The military held meetings on Sunday with the leaders of state and private commercial organizations, senior officials of the commerce, finance ministries and business leaders. Officials from the energy ministry, oil trade and transport companies were also summoned.
"The economy needs to recover. If there is something wrong, we have to find quick solutions," Thawatchai Yongkittikul, secretary general of the Thai Bankers' Association, told reporters, citing coup leader Prayuth.
"The burning issues that need to be solved are the rice-buying scheme and the budget plan for the 2015 fiscal year."
A rice-subsidy scheme organized by Yingluck's government failed, leaving huge stockpiles of the grain and farmers are owed more than $2.5 billion. A military spokesman said it was hoped farmers would begin to get paid in one or two days and every farmer would be paid in a month.
A military official also told 18 newspaper bosses that King Bhumibol Adulyadej would on Monday endorse Prayuth as leader of the ruling military council, a significant formality in a country where the monarchy is the most important institution.
On Saturday, the army said the king had acknowledged the takeover.
An undercurrent of the crisis is anxiety over the issue of royal succession. The king, the world's longest-reigning monarch, is 86 and spent the years from 2009 to 2013 in hospital.
Crown Prince Vajiralongkorn does not command the same devotion as his father, but some Thaksin supporters have recently been making a point of showing their loyalty to the prince.
The military, which has launched 19 successful or attempted coups since the end of absolute monarchy in 1932, has banned gatherings of more than five people and imposed a 10 p.m to 5 a.m. curfew.
But that has not deterred critics who since Friday have held small protests, not just in Bangkok but in the northern city of Chiang Mai. Students and others had also tried to hold protests in the northeastern town of Khon Kaen, a blogger said. The north and northeast are Thaksin's main strongholds.
The small protests appear almost spontaneous and leaderless but the real danger for the military would be a sustained mass campaign by Thaksin's "red shirt" loyalists.
At a meeting in Chiang Mai on Saturday, the army ordered police and officials to stifle anti-army dissent or face transfer.
The latest turmoil in the nearly decade-long clash between the establishment and Thaksin has hurt Southeast Asia's second-biggest economy.
In the first quarter of the year, the economy shrank 2.1 percent. Thais are not spending, and consumer sentiment fell to a 12-year low in the months before the coup.
Many countries have issued travel warnings for Thailand, which was already expecting the lowest number of foreign visitors in five years in 2014. Tourism accounts for about 10 percent of the economy.
The United States condemned the coup and the U.S. State Department has suspended about $3.5 million in military aid, including a portion for training. The Pentagon said it was canceling various training exercises and visits by commanders.
(Additional reporting by Paul Mooney and Erik De Castro; Writing by Robert Birsel; Editing by Jason Neely)