srael on Sunday restricted fuel supplies to the 1.4m Palestinians living in Gaza, part of a crackdown on ­militants operating in the coastal strip and the latest attempt to weaken the grip on the territory of Hamas, the Islamist movement.

Ehud Barak, defence minister, last week gave the green light to a plan to reduce the flow of electricity and fuel into the strip. His decision was prompted by the recent rise in the number of rockets fired from inside Gaza at the Israeli town of Sderot.

The move sparked a furious reaction from aid groups and Palestinian officials, who criticised it as “collective punishment”.

Mojahed Salama, head of the Palestinian Authority’s petrol agency, told Reuters that imports of diesel and petrol were on Sunday 40-50 per cent lower than normal.

Nehro Hisawami, director of the distribution centre at Nahal Oz, the main entry point for liquid fuels into Gaza, said Israeli authorities had allowed in only 300,000 litres of diesel – 50,000 litres less than usual.

The Israeli army confirmed that an order had gone out to reduce fuel supplies, though it denied that the cuts were already taking effect.

“We are going to reduce diesel and petrol for cars, but not for power plants and for generators used in hospitals,” it said.

The army’s comments echoed a statement by Ehud Olmert, Israeli prime minister, who on Friday promised that the cuts would not ­provoke a “humanitarian crisis”.

Gaza’s inhabitants are almost entirely dependent on imports of fuel and other supplies that pass through Israeli-controlled border crossings. The territory suffered a crippling blow to its economy in June, when Israel drastically curbed the flow of goods and raw materials after Hamas took exclusive control of the coastal strip.

Mustafa Barghouthi, a Palestinian lawmaker and former information minister, said the latest Israeli measures against Gaza were “a gross form of collective punishment”.

They violated “all the protections afforded to civilians under occupation by international law”, he said.

The latest escalation comes as Israeli and Palestinian negotiators struggle to find common ground ahead of a planned peace meeting in the US before the end of the year.

Mr Olmert and Mahmoud Abbas, Palestinian president, met on Friday to discuss the meeting.

Officials say the two sides remain far apart on substantive issues.