Iranian President Hassan Rouhani said a nuclear deal sealed with world powers on Tuesday will open "new horizons" now that "this unnecessary crisis" has been resolved.

In a message on his Twitter account, Rouhani said the successful talks had shown "constructive engagement works."

There can now be "a focus on shared challenges", he added, alluding to Sunni Muslim extremists of the Islamic State group, who from their base in Iraq and Syria are launching attacks on both Shiite and Western targets worldwide.