Chinese President Hu Jintao has called on Iran to make a serious response to the international community's concern over its nuclear programme.
Iran may be gauging China's appetite for tougher sanctions
The Chinese leader also said diplomatic efforts should continue in order to achieve a long-term settlement.
Mr Hu made the remarks after talks with top Iranian nuclear negotiator Ali Larijani in Beijing, state TV reported.
It follows last month's UN Security Council decision to impose sanctions on Iran's trade in nuclear technology.
Mr Larijani, who was in Beijing for a two-day visit, delivered a letter to Mr Hu from Iranian President Mahmoud Ahmadinejad.
The two discussed the UN resolution passed last month which bars all countries from selling materials and technology to Iran that could contribute to its nuclear and missile programmes.
At a news conference in Beijing, Mr Larijani said Iran was committed to the peaceful development of nuclear energy.
Iran's chief nuclear negotiator told journalists that Iran would adhere to the terms of the nuclear Non-Proliferation Treaty but said that could change if Iran were threatened.
Correspondents say Iran may be wanting to gauge the appetite in China for tougher sanctions, which the US has pushed for.
China has always faced a delicate balancing act in its dealings with Iran.
Beijing needs Iranian oil and gas for its booming economy, and China supports Iran's right to a nuclear programme.
But as a permanent member of the UN Security Council, it backed last month's resolution imposing sanctions on Iran.