Iran will announce further moves on Monday to scale back compliance with an international nuclear pact that the United States abandoned last year, the semi-official Tasnim news agency reported on Sunday.

"Iran's Atomic Energy Organisation tomorrow at the Arak heavy water site will announce preparatory steps that have been taken to further decrease Tehran's commitments under the deal," Tasnim said, without citing sources.

The organization will announce moves to increase stocks of enriched uranium and production of heavy water at Arak, Tasnim reported.

The United States and the International Atomic Energy Agency believe Iran had a nuclear weapons program that it abandoned. Tehran denies ever having had one.

Iran stopped complying in May with some commitments in the 2015 nuclear deal that was agreed with global powers, after the United States unilaterally withdrew from the accord in 2018 and re-introduced sanctions on Tehran.

Iran said in May it would start enriching uranium at a higher level, unless world powers protected its economy from U.S. sanctions within 60 days.

Tensions between the United States and Iran have ratcheted up further in recent days, with Washington accusing Tehran of carrying out Thursday's attacks on two oil tankers in a vital oil shipping route. Iran has denied having any role.