Rice in Mid East on peace mission

The prisoner release was greeted with jubilant scenes in the West Bank

US Secretary of State Condoleezza Rice has arrived in the Middle East as part of US efforts to secure a peace deal in the region by the end of the year.

Her visit coincides with the release of 198 Palestinian prisoners in what Israel called a goodwill gesture to Palestinian leader Mahmoud Abbas.

They include two convicted killers of Israelis who have been in detention since 1977 and 1979.

Correspondents say Washington's aim for a peace deal this year looks unlikely.

Relations between Israel and the Palestinians have been strained in recent months and both have internal issues.

The BBC's Tim Franks, in Jerusalem, says the Israeli leadership is in flux: the Israeli Prime Minister Ehud Olmert has said he will step down after new internal party elections.

And the Palestinians remain divided between those in charge of the West Bank, with whom the Israelis are talking, and the rival Islamist Hamas faction, in control of the Gaza Strip.

En route to Israel, Ms Rice played down the possibility that details of an interim agreement might be published next month, our correspondent says.

Israeli Foreign Minister Tzipi Livni, who is chief negotiator, has already warned that attempts to bridge gaps prematurely, as she put it, can lead to misunderstandings and violent clashes.

Ms Rice welcomed news of the prisoner release as "a very good step".

'National wedding'

Meanwhile, the prisoner release was greeted with jubilant scenes at the Beituniya checkpoint near Ramallah.

When Israel frees prisoners to weak elements without demanding anything in return, they remain weak Shaul Mofaz Israeli transport minister In pictures: Prisoner release Emotional toll of prisoners issue

They then boarded Palestinian buses for the short journey to Mr Abbas's presidential compound for an official celebration.

Palestinian Prison Affairs Minister Ashraf al-Ajrami said their reception would be like a "national wedding".

Correspondents say it is rare for Israel to free convicted killers of its citizens.

Said al-Attaba, 56, was jailed in 1977 for killing an Israeli woman and Mohammed Ibrahim Abu Ali, 51, was imprisoned in 1979 for killing an Israeli reservist.

Shaul Mofaz, one of the contenders to succeed Israeli Prime Minister Ehud Olmert when he steps down next month, condemned the release.

About 10,000 Palestinians remain in Israeli jails - nearly 700 of these are held in administrative detention without charge or trial.