More casualties were reported Saturday as Turkey continued its cross-border offensive against Kurdish rebels in northern Iraq for a second day.

Kurdish rebels killed 22 Turkish soldiers, a spokesman for the rebel Kurdistan Workers Party (PKK) said. However, the Turkish military reported earlier on Saturday that five of its soldiers have been killed.

Neither that report, nor one that 55 rebels have died since the start of the offensive against the PKK, could be independently confirmed.

An unidentified military officer of the U.S.-led coalition in Iraq told the Associated Press that several hundred Turkish soldiers had crossed the border into the remote mountainous region. The coalition has satellites as well as drones and other surveillance aircraft at its disposal.

Sky-Turk television said about 2,000 Turkish soldiers were in Iraq, while Turkey's NTV television reported a total of 10,000 soldiers.

Both the U.S. and European Union have called for restraint amid fears the incursion could undermine Iraq's only stable region.

"We urge the Turkish government to limit their operations to precise targeting of the PKK, to limit the scope and duration of their operations," said Scott Stanzel, a spokesman for U.S. President George W. Bush.

The Cable News Network quoted security sources as saying the ground offensive against the PKK rebels was planned to last about two weeks.

With files from the Associated Press