Chinese Premier Wen Jiabao and former U.S. President Jimmy Carter Monday voiced optimism over the China-U.S. relationship and the will to work for stronger ties despite ups and downs.

"Since the two countries established diplomatic ties 31 years ago, China-U.S. relations have weathered various tests and always moved forward," Wen said during a meeting with Carter in Beijing.

Wen said it is crucial at this moment for China and the United States to develop a positive, cooperative and all-round bilateral relationship, which requires arduous, long-term efforts from both sides.

At present the two sides should enhance mutual trust, strengthen cooperation and join hands in promoting the recovery of the global economy, he said.

In the long term, the two countries should abide by the principle of mutual respect and treating each other as equals, properly address their disputes, increase common interests, actively push forward all-round cooperation and jointly push for sustained peace and sustainable development for humankind.

"China is ready to work with the U.S. to fend off various risks and continually push forward the relationship," Wen said.

Carter said he was proud of the decision he and late Chinese leader Deng Xiaoping jointly made 31 years ago to establish diplomatic ties between the two countries. He said he had confidence in U.S.-China relationship.

He said he is willing to work for deeper understanding and friendship between the people of the two countries.

Carter is in China for a conference on international sister cities in Shanghai and the fourth China Zhijiang International Peace and Culture Festival in Hunan Province this week.