"We have nothing; we have no reports like that at all," spokesman Major Winfield Danielson told AFP.

Asked if the US military would know if Turkish troops had crossed the border, he replied, "I can't answer that. I don't know if we would."

He added: "The Iraqi government and the Kurdistan Regional Government would be the first to know about something like this. Kurdistan is an autonomous region."

The Turkish army said in Ankara it inflicted "heavy losses" on a group of around 50 members of the armed Kurdish separatist movement PKK in northern Iraq on Saturday.