Mohammed ElBaradei, the director-general of the International Atomic Energy Agency, said: "I urge Iran to be as active and as co-operative as possible in working with the agency to clarify this matter of serious concern."
Al Jazeera's John Terrett in New York said the vote was "not what the West had been hoping for", but in many ways the best it could get after a US intelligence report released in December said Iran had closed its weapons programme in 2003.
Iran has ignored three previous Security Council resolutions demanding it freeze its uranium enrichment programme, which can produce fuel for both nuclear power plants or atomic weapons.
Libya, South Africa and Vietnam had joined Indonesia in expressing reservations about this third set of sanctions against, Iran but decided to vote to support it.
The resolution approved more travel and financial restrictions on named Iranian individuals and companies and makes some restrictions mandatory.
Iran's ambassador to the UN, Mohammad Khazaee, told the council: "The credibility of the Security Council ... is readily downgraded to a mere tool of the national foreign policy of just a few countries."
"Iran cannot and will not accept a requirement that is legally defective" and politically motivated, he added, referring to the resolution's demand for Iran to suspend uranium enrichment and reprocessing activities.
However Israel welcomed the decision, saying the move constituted a "new phase" of pressure put on Iran to renounce its programme.
"This important decision proves that the international community
does not accept Iran's nuclear programme, which threatens stability
and peace in the world," Arye Mekel, a foreign ministry spokesman, told
After the vote, John Sawers, the British ambassador to the UN, read out a statement on behalf of the six world powers which have pushed for sanctions against Iran - Britain, China, France, Germany, Russia and the United States.
Sawers said Resolution 1803 reflected "serious concern" about the proliferation risks of Iran's nuclear programme and for the third time sent a "strong message" to Tehran.
He added that the six had asked Javier Solana, the European Unions' foreign policy chief, to resume talks with Saeed Jalili, Iran's nuclear negotiator.
Two earlier sets of sanctions were approved unanimously in December 2006 and March 2007.