Thailand's national security chief said Monday that a group of Laos-based Thais wanted for spreading anti-monarchy messages had made death threats against the prime minister and his deputy.
The allegation comes as Thailand seeks to extradite the group for slandering the royal family -- an offence punishable by up to 15 years in prison per count.
"The threats came from Thais who are disloyal to the monarchy and ran away to live in Laos...It is the same group that held radio programmes defaming the monarchy," national security chief Thaweep Netniyom told reporters in Bangkok.
The group allegedly issued the death threats against Prime Minister Prayut Chan-O-Cha and his deputy, defence minister Prawit Wongsuwan, on social media.
"They did it to hit back at the government that wants to prosecute them," Thaweep said.
Thailand's military government has tried in vain to extradite a number of royal insult suspects who have fled abroad since its 2014 coup.
Neighbouring Laos has yet to publicly comment on Thailand's efforts to bring the royal defamation suspects home.
Lese majeste prosecutions have skyrocketed under the royalist junta, with courts handing down record jail sentences, often for comments posted online.
The first lese majeste verdict of 2017 saw an anti-junta activist sentenced to 11 years and four months in prison last month for critical comments written on Facebook and in a private message chat.