UN High Commissioner for Human Rights Louise Arbour on Friday urged Israel to exercise restraint in its dealings with the Hamas-led Gaza Strip.

In a statement voicing concern at Israel's decision on Wednesday to declare Gaza a "hostile territory," Arbour said that reducing fuel and power to the tiny territory would place an "unbearable burden" on its 1.5 million people.

The former United Nations war crimes prosecutor and Canadian Supreme Court judge also condemned the indiscriminate firing of rockets into Israel by Palestinian militants in Gaza.

Arbour reminded Israel of its obligations under international humanitarian and human rights law not to use disproportionate means or resort to collective punishment.

Gaza had already paid a "heavy price" from daily violence, isolation and deprivation, she said

Rights groups condemn gov't decision to cut fuel, electricity to Gaza In a joint announcement released Thursday, seven different Israeli rights groups condemned the government's decision to cut back fuel and electricity supplies to the Gaza Strip saying it violated international law by not distinguishing between combatants and civilians.

The statement also said the step constituted collective punishment and would worsen Gaza's existing humanitarian crisis. Since Hamas took control of Gaza in June, Israel and Egypt have closed Gaza's border crossings to nearly everything but humanitarian aid, worsening economic hardship in the Strip.

The government's decision to further isolate Gaza is aimed at doing what Israel's military has failed to do - halt rocket barrages fired nearly daily by Palestinian militants from Gaza into Israel.

Israeli government spokesman David Baker would not respond to the statement, but said Friday that the government's decision on Gaza was vital to protect Israelis.

"Any situation in which Palestinian terrorists fire upon Israeli cities and towns is an untenable situation, one we won't tolerate, and we will use the means necessary in order to enable our citizens to live in peace and quiet once again," Baker said.

The announcement from the Israeli groups, including B'Tselem and the Association for Civil Rights in Israel, came in wake of similar warnings from international organizations like Oxfam and condemnations from the government of Palestinian Authority Chairman Mahmoud Abbas.

Palestinian militants have fired thousands of rockets into Israel since 2001, killing 12 people and making life terrifying for the residents of Israeli communities near Gaza. Gaza's Hamas rulers have done nothing to stop the rocket fire.

Despite numerous incursions that have caused high Palestinian casualties, Israel's military has been unable to halt the barrages. On Wednesday, the government decided to declare Gaza hostile territory and further isolate its residents, cutting back their fuel, electricity and nonessential goods until the rocket fire ceased.

Israeli security officials said Thursday that implementation would begin over the coming days. Fuel for cars and for Gaza's power plant will be drastically reduced, but the diesel fuel that runs hospital generators will be unaffected, the officials said.

The officials spoke on condition of anonymity because they were not authorized to speak to the press.