BANGKOK - Thailand's former Prime Minister Thaksin Shinawatra was moved from a Bangkok prison to a hospital, officials said on Wednesday, following health concerns on his first night in jail after returning from exile.

The Corrections Department said in a statement that Thaksin was transferred to Bangkok's police hospital in the early hours of Wednesday to avoid the risk that could threaten his life after developing symptoms of chest tightness, hypertension, and low blood oxygen levels.

The 74-year-old has several diseases that need to be monitored, and the prison ward is not well equipped to treat his condition, the statement said.

Thaksin was Thailand's premier from 2001 to 2006. He returned to the country on Tuesday after years of self-exile. He was soon put behind bars upon arrival to serve an eight-year sentence due to several convicted charges.