PARIS — Iran on Thursday sought to downplay the importance of intensified economic sanctions against it, even as European Union countries moved closer to agreement on an embargo on Iranian oil, their boldest step so far in the increasingly tense standoff with Iran over its nuclear program.

A final decision by the European Union would not come before the end of the month and would be carried out in stages to avoid major disruptions in global oil supplies. But the move by some of Iran’s most important oil customers appears to underscore the resolve of Western allies to impose on Iran the toughest round of sanctions to date, increasing pressure on Tehran to stop enriching uranium and to negotiate an end to what Western leaders argue is an accelerating program to build a nuclear bomb.

Iran denies military intent and refuses to stop enrichment of uranium for what it describes as civilian purposes. But it has responded to the threat of new U.S. and European sanctions with a series of military and diplomatic threats. It has test-fired new missiles, announced the production of its first nuclear-fuel rod, warned a U.S. aircraft carrier not to return to the Persian Gulf, and threatened to shut the Strait of Hormuz to shipping, which analysts said could drive oil prices up by at least 50 percent.

On Thursday in Tehran, Foreign Minister Ali Akbar Salehi said Iran was “not concerned at all” about an imminent E.U. ban on its oil, vowing that Iran would “weather the storm’’ of what the Economy Minister, Shamseddin Hosseini, likened to “an economic war.’’