Vienna, Tehran: Iran’s president says Tehran and world powers agree on the principles of a final deal on the Iranian nuclear programme but that differences remain on the “details” that still need to be negotiated.

Hassan Rouhani says Iran and the six-nation group — the five permanent members of the UN Security Council plus Germany — have come a long way in sorting out major issues but that they still differ over issues such as “quantity”.

Rouhani did not elaborate. He spoke with lawmakers on Tuesday night, according to the Iranian state television.

The two sides face a November 24 deadline to reach a comprehensive deal. The nuclear talks reportedly remain stuck over the size and output of Iran’s uranium enrichment programme, a possible pathway to nuclear arms.

Iranian dissidents have meanwhile said that Tehran is still researching nuclear arms at facilities it relocated to escape detention.

The Mujahedin-e Khalk, or MEK, cites Iranian government sources it did not identify. It said on Wednesday that Iran’s Organisation of Defensive Information and Research, or SPND, moved its most sensitive weapons research to a new Tehran location “in recent months.”

It says Mohsem Fakhrizadeh, whom it described as a Revolutionary Guard brigadier general, leads the SPND.

Some — but not all — of the MEK’s previous information has been confirmed by Western governments and the UN nuclear agency probing Tehran’s atomic activities.

In announcing sanctions on SPND in August, the US government described it as “primarily responsible for research in the field of nuclear weapons.”

Iran denies working or seeking such arms.