Washington sanctioned Iran's Central Bank as punishment for work that Iran's adversaries in the West believe is geared toward a nuclear weapon. Tehran maintains its nuclear program is for peaceful purposes.
European leaders, meanwhile, are expected to take a stronger line on Tehran by the end of the month.
White House spokesman Jay Carney, during a regular news briefing with reporters, said sanctions should be coordinated to prevent a major oil shock.
"Our belief is that for these sanctions to be most effective, they need to be multilateral and have multilateral participation, they need to be timed and phased in a way that avoids negative repercussions to international oil markets and in ways that might cause more damage to ourselves than to Iran," Carney said.
Iran has threatened to choke off oil shipping lanes through the Strait of Hormuz, a narrow strait in the Persian Gulf that serves as a conduit for a significant portion of the word's oil shipments.
Iran has warned it would close the vital strait before but has never carried out the threat.
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