Returning to Tehran on Friday after a one day visit to China, Ali Larijani told reporters the Russian proposal was "not sufficient for Iran's nuclear energy needs."
"However, one can not say that it is a negative proposal," said Larijani, the secretary of Iran's Supreme National Security Council.
Larijani had been in Beijing seeking China's support against Western efforts to haul Iran before the UN Security Council and face possible sanctions over its nuclear programme.
During his visit he described the Russian proposal as "a useful one, but needs to be discussed further."
Larijani also said Iran was willing to show flexibility but rejected the "language of force", an apparent reference to the threat of UN sanctions.
For its part, China said it supported the Russian proposal and called on other countries to give it consideration.
Workers at a uranium processing
site in Isfahan
"We think the Russian proposal is a good attempt to break this stalemate," Chinese Foreign Ministry spokesman Kong Quan said.
Kong also reiterated China's stance that it preferred diplomatic efforts to any other method of ending the global stand-off over Iran's nuclear programme.
"We always advocate resolving issues through negotiations. Under this context we support all diplomatic efforts to properly resolve the issues."
China's is one of five permanent council members with veto-wielding power and has said it prefers diplomacy in dealing with Iran's disputed nuclear activities.
Meanwhile, Condoleezza Rice, the US secretary of state, has said Iran is "feeling the heat" of international pressure over its nuclear programme and Washington will insist the issue be formally referred to the UN Security Council.
In an interview with Reuters on Thursday, Rice showed little patience with Iran's belated interest in a Russian compromise proposal that would keep the case out of the Security Council.
"I think that says something about the role of (international) pressure in this process. It shows the Iranians are feeling the heat," she said.
"We think the Russian proposal is a good attempt to break this stalemate"
Chinese Foreign Ministry spokesman
The Iranians are "doing nothing but trying to throw up chaff so that they are not referred to the Security Council and people shouldn't let them get away with it ... The time (for a formal referral) has come," she added.
The US and Europe have been lobbying with Beijing to take a tougher stand, and have sought its support for a European-led drive to have Iran brought before the Security Council, which can impose a range of sanctions or other measures.
China, Russia and India are allies and trading partners of Iran and have been reluctant to see Tehran punished or ostracised through the Security Council.
The West fears Iran wants to develop a nuclear bomb, but Tehran says its intentions are peaceful and that it wants only to develop civilian nuclear energy.