BRUSSELS — NATO hailed the Iran nuclear deal on Tuesday as a "historic breakthrough" that would strengthen global security, but urged Tehran to comply with the terms of the accord.

The deal sealed in Vienna aims at ensuring Iran does not obtain the nuclear bomb, relieving sanctions against Tehran and ending decades of tension with the West.

"This agreement represents a historic breakthrough which, once fully implemented, will strengthen international security," said the US-led military alliance's Secretary General Jens Stoltenberg.

"It is critical for Iran to implement the provisions of today's agreement and to fulfil all its international obligations and advance security in the region and beyond," the former Norwegian premier added.

The deal puts strict limits on Iran's nuclear activities for at least a decade and calls for stringent UN oversight in a bid to make it virtually impossible for Iran to get the bomb.

In return, Iran will get sanctions relief although the measures can "snap back" into place if there are any violations.

Stoltenberg praised negotiators in the talks between world powers and Iran for their "perseverance" after 18 days of grueling talks that led to the deal.

The talks grouped Iran with NATO members Britain, France, Germany and the US, plus China and Russia.