Paetongtarn Shinawatra, a daughter of former Thai prime minister Thaksin Shinawatra, received a royal letter of endorsement on Sunday to officially become Thailand's youngest-ever prime minister at the age of 37.

Paetongtarn, the leader of the largest ruling party, Pheu Thai, was elected by Thailand's lower house on Friday to succeed former Prime Minister Srettha Thavisin. He was dismissed by the Constitutional Court, which said his appointment of a Cabinet member had violated the constitution's ethical standards.

Paetongtarn said in a speech at the inauguration ceremony attended by her father that she will listen to all opinions to take the country forward.

Pro-military conservative forces in the ruling coalition are believed to be opposing the political power Thaksin has gained since he returned to Thailand for the first time in 15 years last August.

Thaksin was sent to prison on charges including corruption, but complained of ill health.

He was freed on parole after the king reduced his eight-year sentence to one year. He was officially released after he received a royal pardon.

However, Paetongtarn is in for difficult maneuvering as conservatives are likely to keep forces close to her father in check.