Time is running out for a diplomatic solution to the standoff over Iran's nuclear program, President Barack Obama said Sunday.
"I believe there is a window of time to solve this diplomatically but that window is closing," Obama told reporters.
Iran has maintained its nuclear program is purely peaceful, despite international suspicions. Israel has repeatedly said the option of a military strike against Iran's facilities is on the table, something Obama has pressured the Jewish state not to do.
Still, Obama said earlier this month the U.S. would not hesitate to attack Iran to prevent it from acquiring a nuclear weapon.
Erdogan spoke to Obama about his planned upcoming visit to Iran and said he would also talk to Iranian leaders about the violence in Syria, a Tehran ally.
Representatives from Iran and North Korea are not attending the Seoul summit, nor are the countries on the formal agenda, but both are "dominating talks on the sidelines of the conference that is ostensibly focused on preventing nuclear terrorism," Reuters reported.