Turkey's military said on Friday it had launched a cross-border land offensive backed by fighter jets into northern Iraq on Thursday evening to hunt down Kurdish PKK guerrillas.

Turkish television reported, without citing sources, that 10,000 troops had entered Iraqi territory. NTV said troops had moved 10 km inside Iraq.

'The Turkish Armed Forces, which attach great importance to Iraq's territorial integrity and stability, will return home in the shortest time possible after its goals have been achieved,' the General Staff said in a statement posted on its Web site.

The military's General Staff said the cross-border offensive was launched at 7pm (1700 GMT) on Thursday. A senior US official said the land incursion was 'not the greatest news'.

'A land operation is a whole new level,' deputy assistant secretary of state Matthew Bryza told reporters in Brussels.

He said Washington had been co-operating fully with Turkey in providing intelligence on PKK positions in northern Iraq since last November to enable the Turkish air force to make pinpointed attacks minimising civilian casualties.

The European Union and the United States have in the past raised concern that a major cross-border offensive could destabilise the region, though have not criticised recent small-scale cross-border raids over the past two months.

In Baghdad, Iraqi Foreign Minister Hoshiyar Zebari said his government was not aware of any Turkish ground offensive. Iraqi Prime Minister Nuri al-Maliki called on his Turkish counterpart on Thursday evening to respect Iraq's borders after renewed shelling.

President Jalal Talabani accepted an invitation from Turkish President Abdullah Gul to visit Turkey.

Turkish financial markets dipped slightly on news of the offensive, a possibility that had been mooted by Foreign Minister Ali Babacan on Tuesday and in a statement from Turkey's National Security Council (MGK) after a meeting on Thursday.

Broadcaster CNN Turk said Turkey, which has the second largest army in Nato, had informed Washington and Baghdad about its planned ground offensive.

Turkey says it has the right under international law to hit PKK rebels who take shelter in northern Iraq and have mounted attacks inside Turkey that have killed scores of troops.-Reuters