China is opposed to unilateral sanctions against Iran and has called on parties concerned to solve the Iranian nuclear issue via talks and cooperation, Foreign Ministry spokesman Hong Lei said on Tuesday.

The European Union (EU) on Monday reinforced its sanctions against Iran, including banning imports of natural gas from Iran "over the lack of progress in nuclear talks."

During his daily briefing, Hong said: "We don't think sanctions can solve the issue fundamentally. They can only complicate the issue and escalate the tensions."

He said there was ample room for diplomatic efforts.

"We have always advocated to solve the issue through dialogue and cooperation. We hope that the parties concerned can demonstrate flexibility, strengthen communication and launch a new round of talks as soon as possible," the spokesman said.

The West has accused Iran of secretly developing nuclear weapons under civilian disguise, a charge that has always been denied by Tehran. The US and the EU have imposed several rounds of sanctions to press Iran to give up its uranium enrichment activities.