Tehran, Iran ? In defiant swipes at its foes, Iran said Wednesday it is dramatically closer to mastering the production of nuclear fuel even as the U.S. weighs tougher pressures and Tehran’s suspected shadow war with Israel brings probes far beyond the Middle East.

Iran further struck back at the West by indicating it was on the verge of imposing a midwinter fuel squeeze to Europe in retaliation for a looming boycott of Iranian oil but denied reports earlier in the day that six nations had already been cut off.

The uncompromising messages from Iran, however, came with a counterpoint. The official IRNA news agency said Iran’s top nuclear negotiator, Saeed Jalili, told European Union foreign policy chief Catherine Ashton that Iran is ready to return to talks with the U.S. and other world powers.

The dual strategy — taking nuclear steps while proposing more talks — has become a hallmark of Iran’s dealings for years and some critics have dismissed it as a time-buying tactic. The advances claimed Wednesday could likely feed these views.

In a live TV broadcast, President Mahmoud Ahmadinejad was shown overseeing what was described as the first Iranian-made fuel rod inserted into a research reactor in northern Tehran. Separately, the semiofficial Fars agency reported that a “new generation” of Iranian centrifuges — used to enrich uranium toward nuclear fuel — had gone into operation at the country’s main enrichment facility at Natanz in central Iran.