The United Nations says the latest Turkish cross-border operation into northern Iraq against Kurdish rebels is disrupting the distribution of humanitarian aid in the area.

A UN spokesman said villagers were often forced to flee because of the advancing Turkish troops, preventing them receiving aid supplies.

Northern Iraq has been administered separately from the rest of the country since 1991, remaining under the control of the two main Iraqi Kurdish nationalist groups, and under the protection of the United States and Britain.

Hundreds of Turkish troops have fighting Kurdish rebels for more than a week.