Image caption The cleric, known as Abu Omar, says he was tortured for seven months after being rendered to Egypt

An ex-CIA station chief held in Panama after being convicted in Italy over the kidnap of a terror suspect is '"en route" to the US, officials say.

Former Milan station chief Robert Lady had been released and had boarded a US-bound flight, said American officials.

Lady was sentenced to nine years in jail for his involvement in the 2003 abduction of the man - an Egyptian cleric - in Milan.

The cleric, known as Abu Omar, was allegedly flown to Egypt and tortured.

In 2009, Lady was convicted in absentia with 22 other Americans for their role in his "extraordinary rendition".

He was reportedly arrested on Wednesday near Panama's border with Costa Rica.

According to Italian media reports, an international search warrant for Lady was sought by the justice minister in Italy's previous government in December 2012.

The Milan trial was the first involving extraordinary rendition, the CIA's practice of transferring suspects to countries where torture is permitted.

The practice has been condemned by human rights groups as a violation of international agreements.

Rendition controversy

Hassan Mustafa Osama Nasr, also known as Abu Omar, was considered a terrorism suspect by the US.

He was abducted on a Milan street in February 2003 and transferred between US military bases in Italy and Germany before being brought to Egypt.

Twenty-two CIA agents, including Lady and an air force pilot, were convicted in 2009 of abducting the cleric. Their sentences were upheld last year by Italy's highest appeals court.

Three more Americans, including CIA Rome station chief Jeffrey Castelli, were convicted by an appeals court in February.

None of the 26 convicted has ever appeared in an Italian court, and only two have had any contact with their lawyers.

Lady reportedly rushed back to the US in 2007, when court hearings began in Milan to decide whether to put the 23 Americans on trial.

He said he had opposed the proposal to kidnap the imam, but was overruled.

Italy had previously said Lady was the only one of the 23 Americans that could be extradited, given the length of his sentence.