Iran may purchase advanced weapon systems from foreign suppliers to modernize its armed forces as an arms embargo on Tehran will be lifted by October 2020, a report said Tuesday.

"Iran will be permitted to purchase conventional systems it is unable to

produce domestically, such as advanced fighter aircraft and main battle tanks," said the Pentagon in a new report titled "Iran Military Power."

The report said Tehran is evaluating the purchase of military hardware from Russia and China, detailing potential acquisitions of Russian Su-30 fighters, Yak-130 trainer aircraft and T-90 main battle tanks when the embargo ends.

"Iran has also shown interest in acquiring S-400 air defense systems and Bastian coastal defense systems from Russia," the report added.

Passed in 2015, UN Security Council Resolution (UNSCR) 2231 endorses the Joint Comprehensive Plan of Action (JCPOA) and extends ballistic missile and conventional arms restrictions on Tehran.

In October, U.S. Special Representative for Iran Brian Hook warned that if the embargo is not renewed, that will begin a new arms race in the Middle East.

Iran started to cut its commitments under the 2015 nuclear deal in a retaliatory move following the U.S.’s unilateral decision to withdraw from the agreement between Tehran and the five permanent members of the UN Security Council plus Germany and the European Union.

The U.S. has since embarked on a diplomatic and economic campaign to ramp up pressure on Iran to force it to renegotiate the agreement.

The deal allows Iran to reduce its commitments in case of other parties' breaches. Tehran says the EU must be more active in implementing its part of the obligations, saying it will return to full compliance with the deal once the EU has nullified the U.S. sanctions.