Ayatollah Mojtaba Khamenei was reportedly wounded in the US-Israeli bombardment that killed his father and predecessor and ignited the Middle East war on February 28, and he has not been seen in public since.

But several written messages have been attributed to him and in the latest -- a letter in response to well-wishes from pronatalists -- he urged Iranians to secure great power status by growing their population.

"By earnestly pursuing the correct, necessary policy of population growth, the great Iranian nation will be able to play a major role and experience strategic leaps in the future," he posted on social media platform X.

In a longer version of his remarks carried by state broadcaster IRIB, Khamenei told activists: "It is hoped that your sincere efforts... will lead to fruitful results, God willing."

Iran has a population of around 92 million -- less than half that of neighbouring Pakistan and smaller than Middle East rival Egypt -- but official figures show it is still the 17th most populous nation in the world.

The country's fertility rate has however fallen drastically in recent decades, from 6.5 in 1979, the year of the Islamic revolution, to just 1.7 in 2024, according to World Bank figures.

In 2020, an Iranian health official said state hospitals and clinics had stopped providing vasectomies or handing out contraceptives in order to turbo-charge population growth.

Despite the damage inflicted by recent US and Israeli air and missile strikes -- and the death of Khamenei senior and several senior figures -- Tehran believes it is emerging stronger from the conflict.

Tehran has exchanged proposals for peace negotiations with Washington, but is still demanding sanctions relief and insists on both maintaining control of the Strait of Hormuz and retaining the right to enrich nuclear fuel.

To maintain this regional leadership role and take "long strides toward building the new Islamic-Iranian civilisation", Khamenei said, Iranians must promote a "culture of childbearing".