Rescuers scrambled through the rubble in a desperate search on Monday for survivors of an earthquake that killed at least 264 people in Turkey as residents fled the scenes of devastation.

People living in eastern Van province issued cries for help on Twitter, giving out the addresses of collapsed buildings and the number of people trapped under the debris, as hundreds of rescuers worked round the clock.

Israel said Sunday it had offered its assistance to Turkey after a 7.3 magnitude earthquake struck the eastern part of the country, despite ongoing tensions between the formerly close allies.

But Turkey had said that for the time being, they would not need it.

An earthquake of 7.3 magnitude rocked eastern Turkey on Sunday, killing more than 70 people, with a seismological institute saying up to 1,000 people could lie dead under the rubble of dozens of collapsed buildings.

Turkey's strongest earthquake in years struck Van, a large eastern city populated mainly by Kurds.

Turkey on Saturday kept up a major offensive against Kurdish rebels on its border and in northern Iraq on the third day of operations after rebel attacks killed 24 Turkish soldiers.

The military activity continued on both sides of the border, said an AFP photographer in the southeastern town of Cizre, less than 40 miles (70 kilometres) from the Iraqi frontier.

Turkish jets kept up bombing raids on Kurdish rebel bases in northern Iraq overnight, as the rebels confirmed that some Turkish troops crossed into Iraq, officials and media reports said Friday.

Turkish war planes continued to take off from Diyarbakir, the regional capital of the mainly Kurdish southeast, to strike at Kurdish rebels who killed 24 soldiers in a string of coordinated attacks on Wednesday, local security forces said.

Turkish air force jets bombed Kurdish rebels camps in northern Iraq overnight in response to the attacks which killed 24 soldiers in the southeast, local security sources said Thursday.

Military activity at the air base in mainly Kurdish Diyarbakir province was very intensive throughout the night with many F-16 jets taking off to bomb the hideouts of the separatist Kurdistan Workers' Party (PKK), they said.

Kurdish rebels killed 26 Turkish soldiers and injured 16 Wednesday in simultaneous attacks in southeast Turkey, marking one of the deadliest days for the army in its fight against the separatists since 1984.

The attacks by Kurdistan Workers' Party (PKK) rebels on Turkish troops occurred in eight locations in Cukurca and Yuksekova in Hakkari province near the Iraqi border, during the night from Tuesday to Wednesday, local security sources said.

Turkey claims "very significant contributions" for the release of Israeli soldier Gilad Shalit, Anatolia news agency quoted deputy prime minister Bulent Arinc as saying on Tuesday.

"In this exchange ... and in protecting the life of Shalit until today, Turkey made very significant contributions," Arinc said without elaborating.

Turkey was shelling northern Iraq's autonomous Kurdistan region on Tuesday, a Kurdish rebel spokesman said, in the first report of Turkish bombardment in the area in more than two weeks.

The shelling began Monday night "against Khowakirk and Zab in northeast Dohuk" province, said Dozdar Hammo, a spokesman for the Kurdistan Workers' Party (PKK), which operates out of bases in Kurdistan.

Turkish Foreign Minister Ahmet Davutoglu has met with leaders of Syria's opposition movement urging unity in pursuit of a peaceful transition in the country, a Turkish diplomat said Tuesday.

"The minister met with representatives of the Syrian opposition, for the first time, in Ankara on Monday," the diplomat told Agence France Presse on condition of anonymity.