George Mitchell, the US envoy to the Middle East, is in Jerusalem for another attempt to persuade Israeli and Palestinian leaders to restart peace negotiations.

Mitchell arrived in the region on Thursday for a preparatory meeting two days in advance of a planned visit to the Middle East by Hillary Clinton, the US secretary of state.

The US state department said the two officials' meetings would build on work the administration of Barack Obama, the US president, has been engaged in thus far.

"As Secretary Clinton reported to the president last week, challenges remain as we continue to work with both sides," the Reuters news agency quoted P.J. Crowley, a state department spokesman, as saying.

"Her visit reflects the administration's commitment - and her personal commitment - to work through the challenges we face in pursuit of comprehensive Middle East peace."

Stalled talks

Mitchell met Ehud Barak, the Israeli defence minister, after his arrival on Thursday before holding talks with Binyamin Netanyahu, the Israeli prime minister, on Friday.

It was not immediately clear when he would meet Palestinian leaders.

Israeli-Palestinian peace talks were broken off late last year after Ehud Olmert, Netanyahu's predecessor, resigned amid corruption allegations, sending Israel into early elections that saw Netanyahu return to power after 10 years.

The Palestinians have insisted on a complete freeze of Israeli construction in the occupied West Bank before the peace process can resume.

But Israel has not shown any signs of willingness to halt construction and Mitchell's latest visit to the region is a fresh attempt to revive the talks.

Obama announced in September that the three parties would begin intense contacts in a bid to revive the talks later this autumn, possibly by late October.