Iran foreign minister Zarif 'hopeful' for nuclear deal

Nuclear talks between six world powers and Iran will continue into Wednesday, US officials say.

The US state department said that "enough progress" had been made to merit working through a midnight (22:00 GMT) deadline.

But spokeswoman Marie Harf added that "several difficult issues" still remained.

World powers want to restrict Iran's nuclear programme in return for relief from crippling sanctions.

Ben Bland reports.