The White House is confident there's enough U.N. support for more penalties unless Iran acts soon to prove it's not working on a nuclear weapons program.
The Obama administration has tried to keep a dialogue open with Iran, but there's been little success so far. Still, presidential spokesman Robert Gibbs says it's that approach that has helped reverse Russia's long opposition to further punishing Iran.
But Gibbs didn't mention China on Wednesday. China is also one of the five veto-holding members of the Security Council. Like Russia, China has routinely blocked tougher penalties against Iran and has given no indication it's ready to change course.
Iran says its nuclear program is designed for to produce electricity.