TEHRAN, Iran -- A defiant Iran on Saturday said it had resumed building nuclear centrifuges, saying the move was retaliation for the failure of three European powers to get its file closed at the ...

In early 2009, Iran’s secret program to build nuclear weapons suffered a series of mysterious failures. Centrifuge machines used to purify uranium suddenly spun out of control and tore themselves ...

Iran is building about 3,000 advanced uranium-enrichment centrifuges, Iranian media reported on Sunday, in a development likely to add to Western concerns about the Islamic state's disputed ...

The tubes are centrifuges that produce highly enriched uranium needed to build nuclear weapons.

IR-1 centrifuges use aluminum and a high-strength alloy, known as maraging steel. About one-third of the centrifuges that were deployed at the sites of the recent strike on June 21 are IR-1.