China said on Friday that it did not approve of tougher new sanctions imposed by the European Union on Iran, and welcomed Tehran's offer to return to negotiations on a nuclear fuel swap without conditions.
EU foreign ministers agreed tougher sanctions on Iran on Monday, including action to block oil and gas investment.
Foreign Ministry spokeswoman Jiang Yu said that China still hoped to solve the thorny issues surrounding Iran's nuclear ambitions through negotiations.
"China does not approve of the European Union's unilateral sanctions on Iran," Jiang said in a statement posted on the ministry's website.
"We hope that all relevant parties can support a diplomatic solution and appropriately resolve the Iran nuclear issue through dialogue and negotiations."
China also denounced the United States earlier this month for imposing its own sanctions on Iran, saying Washington should not unilaterally take such steps outside of UN resolutions.
Jiang said in her statement that she welcomed a new Iranian offer to discuss a fuel swap for a Tehran reactor and hoped it would be helpful to efforts to solve "the Iran nuclear issue through talks and negotiations".
Iran was reported this week to have handed a letter to the International Atomic Energy Agency (IAEA) saying that it would return without conditions to talks about a nuclear fuel swap for the Tehran reactor, which makes medical isotopes.
The issue was a central part of Iran's negotiations with global powers which stalled last October, leading to fresh sanctions against the Islamic Republic.
A deal struck in principle with Russia, France and the United States would have seen Iran send some of its low-enriched uranium (LEU) abroad in exchange for specially processed fuel rods needed to keep the Tehran reactor running.
The aim was to address concerns that Iran's own nuclear enrichment programme might be aimed at developing weapons capability, something Tehran denies. The deal unravelled amid Iranian demands for amendments.