By Jonny Dymond
BBC Istanbul correspondent
Turkey and the US have agreed on an action-plan to eradicate the Kurdish paramilitary group, the PKK.
The PKK and Turkey fought a bloody war for over 10 years
The group is thought to have around 5,000 members living in northern Iraq.
Ever since the US occupied Iraq, Turkey has been pressing Washington to crack down on the group which both countries designate as terrorist.
Details of the plan are not clear, but a US official said any military action would be carried out by US troops.
Any large scale Turkish military presence in northern Iraq would be opposed by the Kurdish groups which currently run the area.
This agreement is important for Turkey, as it marks a new stage in its long battle with the PKK.
It is also a sign of improving relations with the US.
The agreement will almost certainly help the Turkish Government in its efforts to persuade parliament to send Turkish troops to help out the US-led coalition.
The parliament will probably consider a request for around 10,000 troops later this month.
Turkey and the PKK fought a bitter war for more than a decade.
More than 30,000 people were killed, and over a million displaced from their homes - largely in the predominantly Kurdish southeastern part of the country.
The PKK have long sought refuge from Turkish troops in the mountains of northern Iraq.