Thailand's military government has detained former prime minister Yingluck Shinawatra and members of her family after summoning her and other ministers for talks.
"We have detained Yingluck, her sister and brother-in-law," a senior military officer said.
The two relatives have held top political posts.
"We will do so for not more than week, that would be too long. We just need to organise matters in the country first," said the officer, who declined to say where Ms Yingluck was being held.
Meanwhile, the Department of Foreign Affairs is advising Irish citizens travelling to Thailand to exercise extreme caution.
The alert was issued after the army staged a coup yesterday following months of political turmoil.
The department urged Irish citizens in Thailand to "exercise extreme caution, monitor developments via media and social media, and follow the instructions of the authorities".
They should also take "extra care to care to avoid any demonstrations, protests or security operations.”
Thailand's military government has banned 155 people including politicians and activists from leaving the country.
A statement read on television said the decision was taken "in order to maintain peace and resolve the conflict".
After the coup, soldiers dispersed rival groups of protesters who had set up camp in and around the capital, Bangkok.
Former prime minister Yingluck Shinawatra arrived at an army facility in Bangkok this morning after she was summoned by the military.
Ms Yingluck was forced to step down on 7 May after the Constitutional Court found her guilty of abuse of power.
A member of her cabinet took over until yesterday's coup.
The military takeover drew swift international condemnation, with the United States saying it was reviewing its military aid and other dealings with its closest ally in southeast Asia.
Thailand's army chief General Prayuth Chan-ocha seized control of the government two days after he declared martial law, saying the military had to restore order and push through reforms after six months of turmoil.
The military declared a curfew from 10pm until 5am, suspended the constitution and detained some politicians.