Thailand's ex-PM Yingluck Shinawatra and a number of family members and politicians have been detained, as leaders of Thursday's military coup tightened their grip on power.
Yingluck and scores of politicians from the deposed government had earlier been ordered to report to the military.
She was kept for several hours and then driven to an undisclosed location.
Army chief Gen Prayuth Chan-ocha also met key officials, telling them reform must come before any elections.
Gen Prayuth summoned governors, business leaders and civil servants to the Bangkok Army Club on Friday.
Six of Thailand's most senior military officers have now been appointed to run the country, with provincial commanders supervising local government.
The BBC's Jonathan Head in Bangkok says that, unlike in previous coups, there have been no promises of a quick return to civilian rule.
Gen Prayuth told the meeting: "I want all civil servants to help organise the country. We must have economic, social and political reforms before elections. If the situation is peaceful, we are ready to return power to the people."
The general said the coup was necessary to "quickly bring the situation back to normal".
One local official leaving the meeting, Arkom Theerasak, told Associated Press: "There will be an election but it will take a while. The general didn't say when."
Yingluck, who had been prime minister until being removed by the judiciary this month, had been ordered to report to the military along with more than 100 other politicians, including acting PM Niwatthamrong Boonsongphaisan.
It was unclear whether Gen Prayuth met either of them.
Some 155 politicians have been barred from leaving the country.
Our correspondent says it is unclear how many people have been detained but they have been separated and held incommunicado at different bases.
Reuters quoted a military officer as saying Yingluck, her sister and brother-in-law had been held.
Thai military spokesman Col Werachon Sukhondhadhpatipak told the BBC those detained were all involved in Thailand's political "conflict" and he stressed the army was neutral and impartial in those that it had held.
Col Werachon said the detentions should not be longer than a week and were intended to keep the detainees away from "tension".
Our correspondent says there were some small and angry protests in Bangkok against the coup earlier on Friday but, although a few people were detained, there has been no serious resistance.
On Thursday the military suspended the constitution and banned political gatherings, saying order was needed after months of turmoil.
The US led widespread international criticism of the coup, saying there was "no justification".