Freed Egyptian politician Ayman Nour says he will not resume his role as head of the opposition party al-Ghad, but would continue to work within its ranks.

Nour said Thursday there is another chief of al-Ghad now, but he would help rebuild the party.

Nour was released Wednesday after spending more than three years in jail on charges he said were politically motivated.

Prosecution sources say Nour was released for health reasons.

Nour placed a distant second to President Hosni Mubarak in 2005, in Egypt's first multi-candidate presidential election.  He was put on trial several months later.

U.S. State Department spokesman Gordon Duguid said Thursday that Washington welcomed the release, particularly since it was made on medical grounds.   He added any discussions with the Egyptian government are "discreet."

The United States had been calling on Egypt to free the opposition leader for some time.  Nour's imprisonment strained relations between Egypt and the United States.  After his conviction, the White House was sharply critical of his detention, as were Democratic Party leaders in Congress.

The U.S.-based advocacy group, Freedom House, also welcomed Nour's release and urged President Mubarak to free Egypt's remaining political prisoners.

Nour, a former member of parliament, was first arrested before the 2005 election but was released long enough to campaign for the presidency.  He was re-arrested, tried and sentenced to five years in prison.