Dozens of Israeli checkpoints and restrictions on motorists' travel on highways in the West Bank amount to illegal collective punishment of Palestinians on territory they claim for a future state, an Israeli human rights group said Tuesday.

A report by Jerusalem-based B'Tselem acknowledges Israel's right to protect its citizens from attack by Palestinian militants, but said the measures it imposes _ 47 checkpoints among them _ go beyond legitimate security needs.

"While some restrictions on movement were originally imposed in response to a specific security threat, today they primarily serve other objectives, among them the creation of a road network that is rapid, convenient and relatively "sterile" of Palestinians for the use of settlers and other Israelis traveling in the West Bank," the report said.

B'Tselem said the checkpoints, permanent closure of many roads, and a ban on vehicles without special permits from 194 miles of main roads hinder Palestinians from reaching health services and workplaces. The restrictions also are an obstacle to Palestinian President Mahmoud Abbas' attempts to maintain order in the West Bank after losing the Gaza Strip to an armed uprising by the Islamic Hamas group, B'Tselem said.

Prime Minister Ehud Olmert has pledged to ease restrictions on Palestinian movement as part of a package of measures to bolster Abbas against Hamas.

But Israel also defends the restrictions as a necessary part of its fight to prevent the movement of militants who wish to attack Israel or Israeli forces or settlers within the West Bank.

"The system that has been established has been very effective in preventing terror attacks and has saved countless lives," Foreign Ministry spokesman Mark Regev said.

Regev said lifting restrictions had to be done with caution to avoid damaging the tentative moves toward reconciliation between Israel and the Palestinians that have begun since Abbas threw Hamas out of his government and set up a Western-leaning administration in the West Bank.

"We understand the importance...of not having an irresponsible Israeli redeployment that would merely create a vacuum that would be exploited by the extremists," he said. "A new wave of terrorist bombings could destroy the current positive momentum."

The rights group also said the "restrictions impair family and social ties."

"Other negative ramifications include a decline in the supply of infrastructure services and in law enforcement in areas under the responsibility of the Palestinian Authority," the report said. "It is also clear that the restrictions result in what is effectively collective punishment."