"At present, between 3,500 and 3,800 PKK militants are based in the north of Iraq," Abdullah Gul said, adding that the Iraqi authorities are taking no action against the PKK.
He said that if Iraq is unable to protect its own borders, then that should be done by coalition forces.
"Turkey has no territorial claims against any country, nor does it have border issues with Iraq. But we are resolved to ensure the security of our citizens and will do all that is necessary," he said.
Gul's statement comes at a time when Turkish authorities are beefing up security in the southeast of the country where Kurdish insurgents have recently stepped up their activities.
Ankara earlier warned about the possibility of moving into northern Iraq to conduct an Army operation against PKK militants, and is now determined to focus on antiterrorism operations on its own soil, primarily in the southeast, Turkish Prime Minister Recep Tayyip Erdogan said.
Last Wednesday, local media reported that the Turkish Army was conducting the largest military operation against Kurdish separatists in the country's southeast in the past few years.
According to the Turkish Cihan news agency, the operation, involving about 50,000 troops, armored vehicles and combat aircraft, is targeting Kurdish militants in 11 provinces in southeastern Turkey and northern Iraq.
Turkey defended its right to move into neighboring Iraq to destroy separatist bases after a suicide attack, which occurred at a Turkish checkpoint June 4, killed at least eight soldiers and wounded six.
Over 40,000 people have been killed in Turkey since 1984 when the PKK started its fight for an ethnic Kurdish state in the southeast of the country.
Its charismatic leader, Abdullah Ocalan, has been imprisoned since 1999 on charges of terrorism, narrowly escaping the death penalty because the EU, whose membership Turkey is seeking, has long lobbied against capital punishment.
Since the 2003 U.S.-led overthrow of Saddam Hussein, Turkish separatist Kurds have received increasing, if unacknowledged, support from those living in the three neighboring provinces of oil-rich northern Iraq, whose population has sought autonomy from Baghdad and where local Peshmerga militia formally took over security functions from U.S. forces earlier this month.
Ethnic Kurds have also been actively driving for autonomy in eastern parts of Syria. The borders between the three countries are still unsecured.
