The CIA I think with some justification has a long relationship with both the Israelis and the Palestinians and a reputation for rather even handedness

Former CIA chief James Woolsey

Correspondents say the Bush administration, which has been reluctant to play a hands-on role in the region, did not want to send a senior mediator back to the Middle East unless it felt some progress could be made.

The CIA had played an intermediary role in the region since 1997, with Mr Tenet personally mediating between top officials to ensure the peace process did not collapse.

Much of the CIA's work has been undermined by the recent violence

The agency's role was formalised by the 1998 Wye River agreement, which called for a high-level committee including representatives from Israel, the Palestinian Authority and the US to meet regularly to discuss security issues.

With varying degrees of success it helped build co-operation and a degree of trust between the Israelis and the Palestinians, by passing intelligence information between the two sides and arbitrating in disputes.

Confidence-building

But in March, President George W Bush suspended the high-profile role, arguing that the two sides should talk to each other directly.

Yasser Arafat is reported to have asked for the agency to continue its role as broker, but this was rejected until violence on the ground had halted.

The Palestinians are said to have trusted the CIA

A report in the Washington Post said the Israelis had initially expressed concern that Mr Arafat was trying to drag the US back into the conflict as a mediator rather than concentrating on improving security.

But this position appears to have changed with an Israeli official being quoted as saying the Palestinian leader had shown positive signs by curtailing violence and that Mr Tenet's involvement would be a "positive reinforcement".

The US says enough progress has been made by both sides on the ceasefire to enable Mr Tenet to carry out confidence-building measures.

But American commentators warn that while the US has described this as a bold move, it is only an "increment".

'Even handedness'

"This is not about shuttle diplomacy. This is not about long negotiations," one unnamed official was quoted in the New York Times as saying.

James Woolsey, a former director of the CIA, says the immediate issue of security is a crucial precursor to longer-term diplomacy.

"Unless the ceasefire can be made to work it is almost impossible I think for anything else to work," Mr Woolsey told the BBC.

And he says it will make it easier for both sides to accept if talks are suggested by a third party, particularly if that party has a reputation for "even handedness".

Washington relations

"The CIA I think with some justification has a long relationship with both the Israelis and the Palestinians and a reputation for rather even handedness," he said.

Mr Tenet's last known trip to the region was in January, when he attended a round of security talks between Israeli and Palestinian security chiefs in Cairo.

Violence dropped off immediately afterwards. But this was short-lived.

It remains to be seen whether the CIA chief's latest visit will have a longer term impact.