Members of the Kurdistan Workers' Party, known by their Kurdish initials PKK, started withdrawing from Turkish territory for northern Iraq this week.
Their departure follows lengthy talks between jailed PKK leader Abdullah Ocalan and the Turkish government. The European Union said the deal may help with its relationship with Turkey but said it would continue to list the PKK as a terrorist organization.
Turkish newspaper Today's Zaman published a statement from the Iraqi Ministry of Foreign Affairs saying PKK members weren't welcome in the country.
Iraqi authorities told the Turkish newspaper they were concerned that PKK guerrillas could make matters worse in a country were the Kurdish and central governments are at odds.
"In the withdrawal process, should members of the PKK come to Kirkuk, it will escalate the already high tensions in the city," an Iraqi source said on condition of anonymity.
The U.S. military shared intelligence with Turkey about PKK activity during the Iraqi war. The Turkish government has sanctioned the use of cross-border attacks to take on the guerrillas.