Yingluck is no longer in military custody, CNN reported, quoting a highly placed source in the Thai military that seized power in a bloodless coup last week, as saying.
A source close to the 46-year-old Yingluck also confirmed that she was released from a military camp, the report said.
The armed forces seized power in a coup on Thursday after months of turmoil that paralysed much of the government and caused deadly clashes in Bangkok.
The military source, who spoke on condition of anonymity because of the sensitivity of the situation, insisted that Yingluck has freedom of movement and communications.
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A close aide to the former prime minister could not confirm when Yingluck was released, and contradicted the military's assertion that she was free to move around.
"I don't think she has freedom of mobility and communication," the source said.
Yingluck is the sister of Thaksin Shinawatra, who was ousted as premier in a military coup in 2006. Thailand has faced a power struggle since Thaksin was ousted by the military as PM in 2006.
The latest unrest began last year, when anti-government protesters embarked on a campaign to oust Yingluck's government. They accuse Yingluck of acting as a proxy for her fugitive brother.
Altogether, around 150 people will be required to appear before the National Council for Peace and Order, a military spokesman said yesterday.
"We want to give them some time to relax and have time to think over the problem," the had spokesman said.
The council wants to "adjust their perception and make them think about the country, think about the Thai people as a whole, not just one particular group," he had said.