Prime Minister Prayuth Chan-ocha, the army chief who led the coup, said Thailand would pursue Yingluck through diplomatic channels and police cooperation using Interpol.
His remarks came a day after the country’s top court found Yingluck guilty of criminal negligence and sentenced her in absentia to five years in prison.
“She is in Dubai,” Prayuth told reporters, adding that the foreign ministry had been tracking Yingluck’s movements.
“The police will now have to proceed and coordinate with the Foreign Ministry and Interpol.”
Thaksin’s Puea Thai Party did not comment to Reuters on Prayuth’s disclosure.
But a source in the United Arab Emirates said Yingluck left Dubai for London on Sept. 11, without giving further details.
The Supreme Court delayed giving its judgment last month after Yingluck failed to show in court and police discovered she had slipped out of the country.
The Thai authorities had not disclosed Yingluck’s whereabouts before, though senior party members had told Reuters she had gone to Dubai where her brother, former prime minister Thaksin Shinawatra, who lives in self-imposed exile to avoid a 2008 jail sentence for graft, has a home.
On Thursday, asked by Reuters whether Yingluck had left Dubai for London, Thai deputy national police chief Srivara Ransibrahmanakul declined to comment.
Photographs posted on the photo-sharing app Instagram by one of Thaksin’s daughters show Thaksin in London since Sept. 15.
None of the photos feature Yingluck.
For more than a decade, Thai politics has been dominated by the power struggle between the Shinawatras and Thailand’s establishment, which includes the armed forces and urban middle class.
The Shinawatras remain popular with rural and poor voters, and the rice subsidy scheme had helped Yingluck shore up her support base to get elected in 2011.
Throughout her trial, Yingluck said she was innocent and not responsible for the day-to-day running of the scheme, arguing that she was a victim of political persecution.
The ruling junta has promised to hold an election in 2018, though changes to the constitution have ensured the military holds on to some role governing the country.
Thai police on Thursday raided Yingluck’s home in eastern Bangkok, armed with a search warrant.
Around a dozen police from the forensics unit entered the large compound carrying gloves and metal boxes, to be met by a lawyer for Yingluck and one of her bodyguards.