Israel is enlarging 88 of its 122 West Bank settlements despite an agreement to halt the spread of Jewish communities in Palestinian territory, the watchdog group Peace Now said Wednesday.

A report by the group, which documented the construction of new homes with aerial photography and on-site visits, heated up the debate here over a key issue for the U.S.-sponsored peace summit planned by year's end.

Israel wants to keep large blocks of settlements in a final peace accord, but the Palestinians demand the entire West Bank for a future state. Under a 2003 U.S.-backed plan known as the "road map," Israel agreed to stop the expansion of settlements as a first step toward negotiations on final borders.

During a visit this week to prepare for the summit, U.S. Secretary of State Condoleezza Rice won renewed pledges from Israel and the Palestinians to abide by the long-ignored road map. But Israeli Prime Minister Ehud Olmert, while acknowledging that both sides had failed to live up to the plan, did not say when Israel would move to stop settlement expansion.

Rafik Husseini, an aide to Palestinian Authority President Mahmoud Abbas, said the evidence of new construction reported by Peace Now was troubling.

"What Israel is doing on the ground is of course an obstacle to all that we are trying to achieve," Husseini said.

The road map requires the Palestinian Authority, as a first step, to start a process of clamping down on armed militant groups that attack Israel.

In recent months, Abbas has reorganized his security forces in the West Bank, collected weapons from scores of militants who agreed to a truce, and begun sharing intelligence on security matters with Israel. However, his forces control only the West Bank; the Islamic militant movement Hamas, which does not recognize Israel's right to exist, dominates in the Gaza Strip.

"Arguably the Palestinians have begun the process," said Martin Indyk, a former U.S. ambassador to Israel. "It's not a great development yet, but they are starting to do things in that realm and beginning to feel that it's time to say to the Israelis, 'Hey, what about your obligations . . . to freeze settlement expansion?' "

Peace Now is an Israeli organization that calls for the abolishment of the settlements and monitors their activity.

Neither the Israeli government nor the Yesha Council, the settler movement, disputed the report's findings. The settlers group confirmed that new Jewish homes are being built on West Bank land, which it refers to as Judea and Samaria and believes was given to Jews by God.

"The Peace Now report proves that settlement has momentum and will not let up for a moment," Yesha spokesman Yishay Hollender said.

According to government data cited in the report, the number of West Bank settlers increased by 5.8% to 267,500 in the first half of this year, more than triple Israel's population growth rate.

About 2.4 million Palestinians live in the West Bank, which Israel captured in the 1967 Middle East War but stopped short of annexing.

In addition to the 122 government-authorized settlements, Peace Now says Jews in the West Bank have set up 105 unauthorized outposts --rural communities that often consist of trailer homes and are intended as the nuclei of future settlements.

Peace Now faulted the government for failing to live up to its commitment to abolish all outposts built after March 2001.

The report says four of the 51 outposts in that category have been completely dismantled. But new ones, it adds, are being built by stealth: To evade a government ban on driving trailer homes into the West Bank, Peace Now reports, settlers smuggle the parts there and then assemble the homes.

Peace Now tried to force the issue last week by asking the Israeli Supreme Court to order an immediate expulsion of settlers from the outposts. Defense Minister Ehud Barak responded by asking for a two-month delay of any court action so the government could try to negotiate a voluntary evacuation of settler outposts.

Peace Now objected to that solution, saying past negotiations have resulted in retroactive legalization of some outposts.