European Union foreign policy Chief Federica Mogherini is also present in the meeting.

It is expected that the ministers of seven countries would finalize talks this day, IRNA reports.

A close source to Iran's nuclear negotiating team said on Tuesday that they will try to conclude talks even they last until overnight.

Before ministerial meeting Iran’s Deputy Foreign Minister Abbas Araqchi held a meeting with the US Undersecretary of State Wendy Sherman on the nuclear negotiations.

A source close to the Iranian nuclear team said that the intense meeting and uninterrupted sessions aim at concluding the issue.

Delegations intend to work on the remaining issues even into the night.

An Iranian source close to the negotiations told IRNA correspondent that the sides insisted on getting into a result during the negotiations, albeit it will extend till night.

Iranian Foreign Minister Mohammad Javad Zarif, and his German, French and Chinese counterparts Frank-Walter Steinmeier, Laurent Fabius and Wang Yi, respectively, were present in the meeting.

Lavrov left Lausanne on Monday evening after taking part in the first round of ministerial talks and is expected to return to Lausanne on Tuesday afternoon.