Iran has begun rebuilding missile-production sites targeted by Israel during its 12-day war in June, satellite images analyzed by The Associated Press show, but a key component is likely still missing — the large mixers needed to produce solid fuel for the weapons.

Reconstituting the missile program is crucial for the Islamic Republic, which believes another round of war with Israel may happen.

The missiles are one of Iran’s few military deterrents after the war decimated its air defense systems — something that Tehran long has insisted will never be included in negotiations with the West.

Missile experts told AP that obtaining the mixers is a goal for Tehran, particularly as it prepares for possible United Nations sanctions to be reimposed on the country later this month.

The sanctions would penalize any development of the missile program, among other measures.

Iranian President Masoud Pezeshkian is due to address the United Nations General Assembly on Wednesday.

Known as planetary mixers, the machines feature blades that revolve around a central point, like orbiting planets, and offer better mixing action than other types of equipment.

Iran could purchase them from China, where experts and U.S. officials say they've purchased missile fuel ingredients and other components in the past.

Iran's mission to the United Nations did not respond to questions about the country's efforts to rebuild its missile program.