ISTANBUL (AP) — Turkey and the United States agree on the need to ramp up support for Sunni Arab forces in Syria to cut off the Islamic State group's access to the Turkish border and to prevent future terror attacks, U.S. Vice President Joe Biden said Saturday.

Speaking during a joint press conference with Turkish Prime Minister Ahmet Davutoglu, Biden said cutting off that access is "a priority for both of our nations, so that we can prevent new fighters and equipment from reaching ISIL and conducting attacks against civilians."

He also met with Turkish President Recep Tayyip Erdogan, capping a two-day visit to Istanbul focused on boosting the fight against Islamic State militants and resolving the crisis in Syria.

Biden also offered his condolences over a Jan. 12 terror attack that killed 12 German tourists in Istanbul. The Turkish authorities say the suicide bomber was linked to the Islamic State.

"We have a robust operation and commitment to defeat ISIL," said Biden, crediting Turkey for increasing efforts to secure its 550-mile (885-kilometer) border with Syria, as well as allowing anti-IS coalition aircraft to use Turkish bases for bombing runs against IS targets.

Biden also acknowledged the threat that Kurdish militants pose to Turkey, calling the PKK, or Kurdistan Workers' Party, "a terrorist group plain and simple." Ankara views its war on terror as a two-prong effort focused on Kurdish militants and IS jihadists who have established cells in Turkey and use the country as a gateway to Syria.

Biden's visit comes ahead of Syria peace talks that were supposed to begin Monday in Geneva but now appear to be delayed due to disagreements over who should represent the Syrian opposition. Davutoglu suggested the United States and Turkey agreed on which groups should be present.