European Union nations approved new sanctions against Iran on Monday, including an assets freeze of the country's biggest bank.

The Bank of Melli is suspected of providing services to Iran's nuclear and ballistic missile programs and, in a similar move, was blacklisted by the United States last year.

The EU said it will also announce Tuesday additional financial and travel sanctions — effective immediately — on several Iranian companies and "senior experts" linked to Tehran's nuclear program.

The 27-nation bloc is also studying sanctions against Iran's oil and gas sector — but such a step would probably take several months to implement, diplomats say.

Monday's sanctions were formally adopted without debate at the beginning of EU talks in Luxembourg. EU leaders agreed on the measure at talks in Brussels on Friday.

Western nations fear Iran's uranium enrichment program could be used to make a nuclear bomb. Iran insists its enrichment work is intended to produce fuel for nuclear reactors that would generate electricity and has vowed to push ahead with uranium enrichment.

The EU's foreign policy chief, Javier Solana, held unsuccessful talks with Iranian officials in Tehran last week in the latest diplomatic overture aimed at convincing them to accept an offer of economic incentives in return for an end to its uranium enrichment program.

In Tehran, independent analyst Saeed Laylaz said the freezing of Bank Melli's assets would lead to the Iranian economy becoming more isolated and more dependent on Chinese products.

But he suggested President Mahmoud Ahmadinejad might stand to benefit. Targeting Iran "drives inflation up," Laylaz said, "but it helps Ahmadinejad's government hide its failures behind the sanction."