The text has been updated; below is an earlier version.
The US and Iran are scheduled to continue peace talks later on Sunday, according to Iranian media.
"End of 15 hours of marathon talks on the first day of talks between Iran and the US in Islamabad," reports the semi-state Iranian news agency Tasnim, according to AFP.
The semi-state news agency Mehr states that the next round of talks will be held after sunrise.
Direct peace talks between Iran and the United States began in the Pakistani capital on Saturday. Sources say differences, including over the Strait of Hormuz, are deadlocked.
The talks, which brought together high-level representatives, are seen as a measure of success, however. In principle, there have been no direct contacts between Washington and Tehran since the Islamic Revolution in 1979.
