Former Israeli Prime Minister Ehud Olmert released a video statement insisting on his innocence before entering prison to begin a 19-month sentence for corruption.
The 70-year-old - who was credited with working towards peace with the Palestinians while in office from 2006 to 2009 - is the first former head of government in Israel to go to prison.
"As prime minister I was charged with the highest responsibility of safeguarding Israel's citizens. Today I am the one to be locked behind bars," he said in a video released to the media.
"At this time, it is important for me to say once more, as I did in court and outside it, that I completely deny the bribery charges I was accused of," Olmert said in the video.
Olmert had his initial six-year sentence cut by Israel's Supreme Court in December. A separate eight-month jail term is pending since his conviction last May in another case related to cash payments he was alleged to have received from an American businessman.
Israeli news website JPost reports that an attacker stabbed at least nine people on a bus in Tel Aviv today.
The report describes the assailant as a "suspected terrorist" and says that he entered Israel illegally.
Pictures from the scene showed police investigators boarding the bus and a number of ambulances.
At least two commuters were stabbed by an unknown assailant on a bus in central Tel Aviv today, Israeli police said.
The assailant, who tried to escape the scene, was shot by police and lightly wounded in the leg before being apprehended, police spokeswoman Luba Samri said.
Local media reports said one of the victims is in serious condition.
Israeli police have said that an explosion has gone off in a car in Tel Aviv but that there is a "strong possibility" it is a criminal act.
Associated Press report that police spokesman Micky Rosenfeld said he believed the explosion near a bus was criminally motivated, though he could not definitively rule out that it was political violence.
Rescue services spokesman Zaki Heller says preliminary reports from the scene indicated seven to 10 people were wounded in the explosion.
Several people have been hurt after a car exploded in Tel Aviv according to initial reports from Reuters.
Police say the incident appears to be criminal related and not a Palestinian bombing.
Police blamed terrorists for the attack in Tel Aviv, which happened as the bus drove along a street near the Israeli Defence Ministry. The explosion could jeopardise international efforts to agree a ceasefire between Israel and Gaza, as Nina Nannar explains.
The Foreign Secretary William Hague has said "the UK is deeply concerned at emerging reports of a bomb attack on a bus in Tel Aviv":
Two rockets headed for Tel Aviv have been intercepted by the Israeli 'Iron Dome' air defence system, according to Israeli media reports.