Iran nuclear talks in Vienna
Iran nuclear talks in Vienna Reuters

An historic nuclear deal between Iran and world powers could be reached quickly if Tehran is ready to take the last steps, a German government source close to Foreign Minister Frank-Walter Steinmeier said on Sunday, Reuters reported.

"From the viewpoint of the minister, there are only a few elements missing for a watertight agreement with Iran," the source told the news agency on condition of anonymity.

"Everything can still fail, but we are indeed very close to reaching the goal... Negotiations are currently in the absolute final phase and are running intensely through the night," the source added.

Earlier Sunday it was reported that Iran and the six world powers were close to reaching a nuclear deal, but the Iranian foreign minister said no agreement would be announced before Monday at the earliest.

"We still have got work to do tomorrow," Iranian Foreign Minister Mohammad Javad Zarif told reporters, adding, "No deal today."

The talks on a permanent deal between Iran and six world powers, which have already been extended several times and were to end Friday, were extended yet again through the weekend.

Major disagreements in the talks have included Iran's refusal to allow inspections on sensitive nuclear sites, its refusal to disclose the military aspects of its nuclear program, and in a newly added demand, Iran has called to end the UN arms embargo on the Islamic regime.