Iran and the global nuclear watchdog, the International Atomic Energy Agency have agreed on temporary measures to offset Iran's decision to restrict access to inspectors.

IAEA Chief Rafael Grossi told reporters, after a visit to Iran that it would enable the agency to retain the necessary degree of monitoring and verification work.

It comes ahead of a deadline set by Iran to stop intrusive checks of sites unless US sanctions are lifted.

Tensions have soared since the US left a nuclear deal with Iran in 2018.