U.S. President Barack Obama signed a sweeping defense funding bill on Saturday that includes new sanctions on financial institutions dealing with Iran's central bank, but cited concerns about sections that expand the U.S. military's authority over terrorism suspects and limit his powers in foreign affairs.

"The fact that I support this bill as a whole does not mean I agree with everything in it," Obama said in a statement, citing limits on transferring detainees from the U.S. base at Guantanamo Bay, Cuba, and requirements he notify Congress before sharing some defense missile information with Russia as problematic.

Open gallery view U.S. President Barack Obama. Credit: Reuters

The bill, approved by Congress last week, aims with its Iran sanctions to reduce Tehran's oil revenues but gives the U.S. president powers to waive penalties as required.

Senior U.S. officials said Washington was engaging with its foreign partners to ensure the sanctions can work without harming global energy markets, and stressed the U.S. strategy for engaging with Iran was unchanged by the bill.

Earlier on Saturday, a European Union foreign policy spokesman said the EU is open to meaningful talks with Iran provided there are no preconditions on the Iranian side.

All talks between Iran and major powers, including the latest round in January in Istanbul, have failed so far to achieve any tangible result.

The main reason is that Iran has constantly rejected the key Western demand - suspension of its uranium enrichment plan as a sign of goodwill until the peaceful nature of the Iranian nuclear programs are proven.

