RAMALLAH, West Bank  The Palestinian West Bank, besieged by Israeli occupation, political division and weak leadership, got a boost on Monday: the announcement of a plan, led by the American government, to help tens of thousands of people buy homes.

The plan, which establishes a $500 million mortgage company, aims to build 10 new neighborhoods over the next five years and, in the process, create thousands of jobs in construction and real estate. In doing so, it could improve the depressed local economy and the political prospects of the Palestinian president, Mahmoud Abbas, of the relatively pro-West Fatah party.

Mr. Abbas, who has been engaged in peace talks with Israel’s prime minister, Ehud Olmert, will be in Washington next week to see President Bush, who hopes to have a Palestinian-Israeli peace outline before his term ends.

A secondary aim of the housing program is to send a message to the Gaza Strip, run by the Islamist party Hamas, that its citizens, too, could benefit from international generosity and economic progress if they restore Fatah’s authority, overturned by Hamas forces in a battle last June.