Ehud Olmert, 70, former Prime Minister of Israel, once renowned for his efforts to make peace with the Palestinians, arrived at the Maasiyahu prison in the central city of Ramle to start a 19-month term for bribery and obstruction of justice.

"You can imagine how painful and strange this change is to me, my family, loved ones and supporters. I deny all the bribe charges attributed to me," said Olmert in a video message that he released prior to beginning his sentence, reports AFP.

"...over the course of my extensive career I also made mistakes, though none of them were criminal by nature in my opinion," Olmert continued. "I'm paying dearly for some of them today, perhaps too dear.

"With a very heavy heart, I'm accepting my sentence today. Nobody is above the law."

Olmert had been convicted of bribery in 2014 and was given a six-year sentence. The allegations were based on his term as mayor of Jerusalem. The sentence was reduced to 18 months in December 2015. Charges of obstruction of justice added another month last week.

"At this hour it is important for me to say again ... I reject outright all the corruption allegations against me," said Olmert who was escorted to the prison by officers from Israel's Shin Bet domestic security agency, reports the Associated Press.

"Today I am a former prime minister who stands to serve a prison sentence. This is an unusual and grave development, which some will see as confirmation of the Israeli democracy's might. But in the same breath I would like to raise the possibility that the legal case against me snowballed due to non-judicial reasons...Perhaps once time passes the public could examine this sad moment through critical and balanced eyes," he said, according to Haaretz.

Olmert was found guilty of accepting a 500,000-shekel ($129,000, £89,000) bribe from developers of one real estate project and a 60,000-shekel bribe in connection with another. The Supreme Court later cleared him of charges regarding the 500,000-shekel bribe.