Tehran said the move was "giant step" in its nuclear program but the country may not be able to convert the rods into fuel, Arutz Sheva reported.
The Israeli broadcaster noted analysts say the regime of Iranian President Mahmoud Ahmadinejad often has made exaggerated claims, such as the development of long-range missiles.
Iran said the 20 percent-enriched uranium rods were inserted into a "research reactor" in Tehran.
"We have started enriching uranium to 20 percent to build nuclear fuel rods since Western countries are reluctant to provide us with assistance," Iranian deputy nuclear negotiator Ali Bagheri told the Russian news agency RIA Novosti.
Iran had said last month domestically made nuclear fuel rods had been tested successfully.
Iran has said its nuclear program is for peaceful purposes, but Western countries have tightened sanctions amid concerns the country is working to develop nuclear weapons.