Vienna: There are still “difficult issues” to be resolved in nuclear talks with Iran, US Secretary of State John Kerry said on Saturday. The top US diplomat made the remarks on a Twitter post after meeting with his Iranian counterpart, Mohammad Javad Zarif, for 90 minutes on Saturday.

Zarif and Kerry resumed talks in the Austrian capital, Vienna, in a bid to iron out the remaining disagreements over a final deal on Tehran’s nuclear programme.

The top diplomats met as talks entered their 15th straight day in Vienna. Kerry had told reporters on Friday that “progress has been made” in negotiations between Iran and the P5+1 group of countries. This round of negotiations is seen as the last push to resolve the issue.