Several thousand Turkish troops crossed into northern Iraq to chase Kurdish guerrillas who operate from bases there.
Two senior security officials, speaking on condition of anonymity because they were not authorized to speak to the media, said the raid was limited in scope and that it did not constitute the kind of large incursion that Turkish leaders have been discussing in recent weeks.
"It is not a major offensive and the number of troops is not in the tens of thousands," one of the officials told the AP by telephone. The official is based in southeast Turkey, where the military has been battling separatist Kurdish rebels since they took up arms in 1984.
The officials did not say where the Turkish force was operating in northern Iraq, nor did he say how long they would be there.
The officials said any confrontation with Iraqi Kurdish groups, who have warned against a Turkish incursion, could trigger a larger cross-border operation. The Turkish military has asked the government in Ankara to approve such an incursion, but the government has not given formal approval.
An official at military headquarters in Ankara declined to confirm or deny the report that Turkish troops had entered Iraq.