Palestinians will ask international donors for $4 billion to start rebuilding the Gaza Strip over the next two years after the territory was left devastated from 50 days of military conflict with Israel.

The request is contained in a report e-mailed today by the Palestinian Authority in advance of an annual donor meeting in New York scheduled for Sept. 22. It says $623 million will be required for the first year. Estimates for the cost of reconstruction over 10 years have ranged from $8 billion to $12 billion.

“At this critical time we particularly call on our Arab brothers and international partners to meet their commitments towards budget support,” the authority said in a 39-page report.

Israel and the governing authority led by Palestinian President Mahmoud Abbas reached an agreement brokered by the United Nations Sept. 16 that will allow reconstruction work to begin. The pact was designed to address Israeli concerns that construction materials would be diverted to Hamas, the militant group that has ruled Gaza for the past seven years, to rebuild tunnels used during the conflict to stage cross-border attacks.

Hamas agreed in June to form a joint government with Abbas’s Fatah party, which rules the West Bank. Fatah was kicked out of Gaza in 2007 amid violent clashes that ended a previous unity agreement.

The seven-week Gaza war killed more than 2,100 Palestinians and 70 Israelis, and destroyed thousands of Palestinian homes, before it ended with a cease-fire on Aug. 26. Hamas and other Palestinian militant groups fired more than 3,000 rockets and mortars into Israel during the period, according to army statistics.

The report to the donors projects a 3.7 percent contraction in the combined West Bank and Gaza economy after years of slowing growth. A study by the World Bank released two days ago found that every second person in Gaza is unemployed, while one in six in the West Bank has no job. One quarter of Palestinians live in poverty, the Washington-based bank said.

To contact the reporters on this story: Jonathan Ferziger in Tel Aviv at [email protected]; Fadwa Hodali in Ramallah at [email protected] To contact the editors responsible for this story: Alaa Shahine at [email protected] Mark Williams, Karl Maier