The US officials are William Burns, Assistant Secretary of State for Middle East Affairs, Steve Hardly, Deputy National Security Adviser and Elliot Abrams, Middle East Director of Bush's National Security Council, reports Aljazeera's correspondent.
"The delegation may also meet Palestinian officials," the correspondent added.
The US delegation was due to visit Israel last week to discuss the "unilateral disengagement plan", but their visit was postponed till Wednesday as Sharon was not in a good health.
The correspondent said the US delegation's visit to Israel was also aimed at paving the way for possible talks between Sharon and US President George Bush early next month.
Diplomatic sources, reports Reuters, have said the envoys will urge Sharon to stick to reciprocal processes envisaged by a US-backed peace "road map" and to reroute the barrier, which Israel says is necessary for its "security".
The road map takes as its premise that everything should be done in consultation (between Israelis and Palestinians)," a Western diplomatic source said.
William Burns (R), head of Middle
East Affairs will lead US envoy
The envoys' mission is seen as crucial to a US decision on whether to back Sharon's plan to remove most Jewish settlements in the Gaza Strip, which Israel seized with the West Bank in the 1967 Middle East war.
An Israeli political source said Sharon would give the envoys details on his "disengagement plan" for the settlements.
"We intend to unveil the plan in its entirety in Washington next week, as part of preparations for a summit with President Bush," the source said.
Trouble within Likud
Sharon's Gaza settlement plan has already run into trouble from within Sharon's governing coalition and his own Likud party and sparked outrage among settlers.
Sharon will unveil details of his
It foresees the dismantling of 17 Gaza settlements and is part of a series of unilateral measures envisaged by Sharon in the wake of the breakdown of the peace process with the Palestinians.
The plan also involves dismantling a few isolated West Bank settlements.
The Israeli daily Haaretz reported on Tuesday the United States would ask Israel to coordinate its Gaza pullout with the Palestinian Authority "to avoid any chaos that might emerge in the areas Israel quits."
ICRC criticises barrier
The International Committee of the Red Cross (ICRC) has said Israel's controversial barrier is a violation of international humanitarian law in its current form.
In a statement from its Geneva headquarters, the ICRC also called on the Israeli government "not to plan, construct or maintain this barrier within occupied (Palestinian) territory".
"The measures taken by the Israeli authorities linked to the construction of the Barrier in occupied territory go far beyond what is permissible for an occupying power under international humanitarian law"
International Committee of the Red Cross (ICRC)
It said the barrier - a network of metal fences and concrete walls - barred thousands of Palestinian residents stranded on its western side from adequate access to basic services like water, health care and education.
"The ICRC's opinion is that the West Bank Barrier, in as far as its route deviates from the 'Green Line' into occupied territory, is contrary to IHL (international humanitarian law)," the statement said.
And a senior ICRC official said if the barrier were moved back to the Green Line - the boundary before Israel seized the West Bank in the 1967 Middle East War - "that would solve many of the problems as far as we are concerned".
But the statement said the problems the current barrier posed for Palestinians "clearly demonstrate that it runs counter to Israel's obligation .... to ensure the humane treatment and well-being of the civilian population living under its occupation".
"The measures taken by the Israeli authorities linked to the construction of the Barrier in occupied territory go far beyond what is permissible for an occupying power under international humanitarian law," it declared.