China on Thursday called on concerned sides to grasp opportunities in the upcoming Geneva talks on Iran's nuclear program, as Iran's top legislator is visiting Beijing.

"There has been positive momentum in the current dialogue and new opportunities have emerged," said Foreign Ministry spokeswoman Hua Chunying at a regular press briefing.

China hopes concerned sides adopt practical and flexible principles, narrow differences and seek common ground so as to establish an environment for an all-round solution to Iran's nuclear issue, she said.

It is expected that a second round of talks will soon be held in Geneva between Iran and the five permanent members of the United Nations Security Council, namely China, the United States, Russia, Britain and France, plus Germany.

Talks between the UN nuclear agency and Iran earlier this week were "very productive," according to the International Atomic Energy Agency, which raised hopes for a breakthrough in the next Geneva talks.

Hua said that Chinese President Xi Jinping and top legislator Zhang Dejiang met with or held talks with Iran's Majlis (parliament) Speaker Ali Larijani.

President Xi hailed the importance of China-Iran relations and pledged further constructive efforts in seeking a peaceful solution for the nuclear issue within the G5+1 mechanism.

Iran is long suspected of conducting experiments on developing nuclear weapons, an allegation which Tehran had denied, saying the claims are influenced by misleading intelligence from Western spy agencies.