Extremists from war-torn Syria are slipping into Turkey despite heightened security precautions, Turkish President Abdullah Gul was quoted as saying on Monday.
"We aren't managing to prevent terrorist infiltrations despite all precautions taken and the deployment of cannons and tanks" along the Turkish-Syrian border, Gul told Turkish press from New York, where he is attending the UN General Assembly.
"Radical groups are a big worry when it comes to our security," the Hurriyet daily quoted him as saying.
Turkey, which shares a 900-kilometre (560-mile) border with Syria, is currently sheltering more than 500,000 Syrians who have fled the fighting in their country that has killed more than 100,000 people since March 2011.
Last week, Turkey temporarily shut part of its border after fighting between Syrian rebels and an Al-Qaeda front group in the northern town of Azaz.