Former Israeli president Moshe Katsav began serving a seven-year prison term for rape on Wednesday, professing his innocence and saying he was being buried alive.

The case has captivated the country for more than five years and marked the first time a former Israeli head of state has been jailed. Officials say it proves no one is above the law.

Katsav, 66, was president from 2000 to 2007. He was convicted last year of twice raping an aide when he was a cabinet minister in the late 1990s and sexually assaulting two other women who worked for him while he was president.

The day will come when the truth will come out, he said, a pained expression on his face as he pushed through a crowd of friends and reporters outside his home before being driven off to prison.

The conscience of those who committed this injustice will certainly awaken and you will see that you buried a man alive.

Katsav was sentenced in March to seven years in prison. He has consistently denied any wrongdoing, but three Supreme Court justices ruled unanimously against his appeal last month. He has asked the court for another hearing with an expanded panel.

Today a bloody, unrelenting five-and-a-half-year struggle is ending in frustration and rage. I know, and all who know me know, that the accusations are false, Katsav said before entering Maasiyahu prison, where his cellmate is expected to be a former health minister jailed for taking bribes.

Katsav's ascent to the presidency, an institution traditionally above Israel's rough-and-tumble political scene, was almost as dramatic as his downfall.

At 24, the Iranian-born Katsav became Israel's youngest mayor, a symbol for Sephardim, or Jews of Middle Eastern descent, struggling to climb the political and social ladder in a country long led by Jews of European origin.

As a member of the right-wing Likud party, he went on to hold a number of cabinet posts. Parliament elected him president in a surprise victory over Shimon Peres, Israel's Nobel Peace Prize-winning elder statesman, who now holds the office.

In 2007 a long investigation into rape allegations forced Katsav to step down from the presidency in disgrace. His resignation had little impact on Israeli government functions, as the presidency is largely a ceremonial position.

(Editing by Peter Graff)