The UN nuclear watchdog and Iran have agreed to extend an agreement to monitor Tehran's nuclear activities by one month, the International Atomic Energy Agency (IAEA) said Monday.

"The equipment and the verification and the monitoring activities that we agreed will continue as they are now for one month expiring on June 24, 2021," IAEA Director General Rafael Grossi told a news conference.

Iran in late February limited the IAEA's access to nuclear sites it had been monitoring as part of the 2015 landmark deal. An agreement, reached on February 21 for a duration of three months, allowed some inspections to continue.

Grossi said that besides extending that understanding, Tehran had also agreed that information collected so far by agency equipment in Iran would not be erased.

He said the outcome of this "long discussion" was "important" but the situation was "not ideal."

"We should all be reminded that the temporary understanding is a sort of stop-gap measure. It is to avoid flying completely blind," he said. 

The 2015 accord, which had Iran curtail its nuclear program in return for sanctions relief, started to unravel in 2018 when the U.S. withdrew and reimposed sanctions.

"The Director General of the IAEA today (Monday) has been informed of Iran's decision to extend the agreement for a month," Kazem Gharibabadi, Tehran's ambassador to the Vienna-based UN agency, was quoted by state media as saying.

"I recommend that they use this opportunity, which has been provided in good faith by Iran, and lift all the sanctions in a practical and verifiable manner," Gharibabadi said. 

Iran's move to curb IAEA access arose from parliamentary legislation widely seen as pressure on U.S. President Joe Biden's administration to return to the nuclear pact and lift sanctions. 

Talks by Iran and world powers will resume in Vienna this week on the nuclear deal.

(With input from agencies)