Hamas Islamists fired their longest-range rockets at a southern Israeli city on Friday after an Israeli air force attack on their Gaza stronghold, in the 11th day of skirmishes threatening a five-month-old truce.

A statement from the armed wing of the Islamist group said Hamas fired five 1960s-era, Soviet-made Grad rockets at an Israeli town, the longest range weapon they have claimed to shoot at the Jewish state.

Israeli rescue services said five rockets struck the southern coastal city of Ashkelon but caused no casualties. The Grad has a maximum range of 25 km (15 miles).

Palestinian medical workers said two Hamas fighters were wounded in a morning strike by the Israeli air force, which an Israeli military spokesman said was ordered in response to a Hamas rocket attack.

Hamas said it fired 8 shorter-range Kassam rockets in response, aimed at the city of Sderot.

Two hit the town causing damage to buildings, Israeli police spokesman Micky Rosenfeld said. One Israeli was treated for shrapnel wounds, and a number of people were treated for shock.

'Fortunately there were no casualties but there was a lot of damage,' said Micha Ben Alain, whose kibbutz near Sderot was hit. 'Windows were smashed and doors were torn apart.'

'The defense minister must give the army an immediate order to halt the shootings,' said Sderot's mayor David Buskila.

Israel has closed border crossings with Gaza, halting food and fuel supplies to the blockaded enclave, between Israel and Egypt on the Mediterranean coast. Hamas Islamists who control the territory do not recognize Israel's right to exist.

A senior Israel defense official on Friday said that 'due to the continued rocket fire the crossings are shut today ... there is no intent to open them today.'

United Nations aid agencies supplying Gaza said they were out of food to distribute to 750,000 Palestinians.

'People are going to start getting hungry,' said U.N. spokesman Christopher Gunness.

The EU urged Israel to let food, medicine and fuel through to the Palestinians, and urged restraint by both sides.-Reuters