BAGHDAD (Reuters) - Iraq fears that a prolonged Turkish incursion into northern Iraq could trigger clashes between Turkish troops and Iraqi Kurdish Peshmerga security forces, the country's national security adviser said on Monday.

Mowaffaq al-Rubaie said such fighting could have "very serious consequences" for a part of Iraq that has been relatively stable compared with the rest of the country.

"The ... longer Turkish soldiers stay inside Iraqi territory, the more likely this is going to happen," Rubaie told reporters in Baghdad when asked if he was concerned about clashes between Turkish and Peshmerga forces breaking out.

So far the battle-hardened Peshmerga have stayed on the sidelines of the Turkish military operation, which is taking place in a sparsely populated mountainous region. Kurdish officials regard the area as outside their control.

While Iraqi Kurds have little sympathy for the aims of the PKK, there is widespread anger over the incursion.