SARI, Iran  —  President Mahmoud Ahmadinejad on Tuesday warned Europe against backing proposed U.N. measures against its nuclear program, saying Iran would respond by downgrading relations with the EU.

Iran is concerned about moves at the U.N. Security Council to penalize it for refusing to cease uranium enrichment, a process that produces the material for nuclear reactors or bombs. The European Union has been supporting the United States in pushing for tougher U.N. penalties than Russia and China would like to see.

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French Foreign Minister Philippe Douste-Blazy said Monday that the leading powers at the U.N. were nearing an agreement on a Security Council resolution.

Speaking to a crowd in this northern provincial capital, the president addressed the member states of the European Union, saying: "I'm telling you in plain language that as of now, if you try, whether through propaganda or international organizations, to take steps against the rights of the Iranian nation, the Iranian nation will consider it an act of hostility.

"And if you insist on pursuing this path, it (Iran) will reconsider its relations with you," he said.

Iran says it is entitled as a signatory to the Nuclear Nonproliferation Treaty to enrich uranium for peaceful purposes. But the U.N. nuclear watchdog, the International Atomic Energy Agency, is concerned about Iran's record of concealing signficant aspects of its nuclear research and says it has failed to answer all questions about its atomic program.

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