Iran has said its scientists have produced the nation's first nuclear fuel rod, a feat of engineering the West doubted Tehran was able to do.
The announcement comes after Iran said it was compelled to manufacture fuel rods on its own since international sanctions banned Tehran from buying them on foreign markets.
Nuclear fuel rods contain pellets of enriched uranium that provide fuel for nuclear power plants.
Iran's atomic energy agency's website says the first domestically made rod has already been inserted into the core of Tehran's research nuclear reactor.
It is unclear if the rod contained pellets or was inserted empty, as part of a test.
The West fears Iran's uranium enrichment programme is geared toward making atomic weapons, a charge Tehran denies.