Israeli PM Ehud Olmert has said he has received candid reassurance from China that the country opposes any plans by Iran to develop nuclear weapons.
Mr Olmert said the talks were both positive and surprising
Mr Olmert, in China as part of a three-day visit, met his Chinese counterpart Wen Jibao.
Speaking after the discussions, Mr Olmert said he was "positively surprised" by what he had heard.
The US and EU claim Iran is seeking nuclear weapons, but Iran says its programme is entirely peaceful.
"China made it absolutely clear that it opposes an Iran with a nuclear bomb," Mr Olmert told reporters after the 90-minute meeting with the Chinese premier.
He said that he believed Iran had the nuclear knowledge to reach the "threshold" where it could begin to build nuclear bombs.
"I believe Iran will try and reach it and I believe international pressure will prevent it," he said.
Israel is pushing for tougher measures against Iran if it continues to ignore a UN resolution calling on it to halt work on its nuclear programme.
China, a permanent member of the UN Security Council, has so far indicated it would prefer to continue talks with Tehran.
China's official news agency, Xinhua, quoted Mr Wen as telling Mr Olmert that the country, "will continue to play a constructive role in promoting the settlement of the [Iran] issue."
Analysts say that China's hunger for Iranian gas and oil to fuel its economy might soften its stance towards the country.
Mr Olmert's trip to China comes just days after a visit by Iran's nuclear negotiator, who was in Beijing last week.
Trade relations were also high on the agenda.
Business between China and Israel is booming - last year it was worth more than $700m, up by a third on the previous 12 months.
The two leaders signed agreements on importing Israeli citrus fruit and water purification technology, as well as improving cultural ties between the countries.
China also has a special personal significance for Mr Olmert. His parents took refuge in the country in the early 1900s, after fleeing persecution in Russia.
In the past Mr Olmert has talked of having a spiritual tie with China.