Authorities on Monday acknowledged that Iran had broken a limit placed on its stockpile of low-enriched uranium.
An increasing stockpile and higher enrichment shrinks the estimated one-year window Iran would need to produce enough material for a nuclear bomb, something Tehran denies it wants but the nuclear deal sought to prevent.
The US has rushed an aircraft carrier, B-52 bombers and F-22 fighters to the region and Iran recently shot down a US military surveillance drone.
Speaking at a cabinet meeting in Tehran, Mr Rouhani's comments seemed to signal that Europe has yet to offer anything to alleviate the pain of the renewed US sanctions targeting its oil industry and senior officials.
Iran's nuclear deal bars it from enriching uranium above 3.67%, which is enough for nuclear power plants but far below the 90% needed for weapon-grade levels.
"In any amount that we want, any amount that is required, we will take over 3.67%," Mr Rouhani said.