WASHINGTON  -- The 4th China-US Strategic Economic Dialogue (SED) has been a great success, particularly in boosting the mutual trust between the two countries, a senior Chinese official said Wednesday.

"For us, the most important highlight and the biggest accomplishment (of the SED) is the growing mutual confidence between our two countries," Chinese Assistant Minister of Finance Zhu Guangyao told a news briefing here shortly after the end of the two-day SED meeting in Annapolis, Maryland.

"Only with mutual trust can China and the United States work together to strengthen communication and exchange, and expand cooperation in all areas," Zhu said.

"For many of the results and progress that came out of the SED, the very foundation of that achievement is mutual trust," he added.

Zhu said there are two milestone accomplishments of the SED. The first is that China and the US signed a 10-year cooperation framework on energy and environment.

"This is an area where the two countries will work together to tackle the most important policy issues," he said, noting that both China and the United States, as well as the world at large, are faced with great challenges in the area.

Another achievement is that the two sides jointly announced they will launch the formal negotiation on a bilateral investment treaty, Zhu said.

This will have a far-reaching and great impact on the investment environment in both countries, on bilateral trade relations, and also on global trade relations, he added.

Both sides agreed that the two above-mentioned achievements are the biggest success of the SED, Zhu said.

The SED is a dialogue mechanism initiated by Chinese President Hu Jintao and US President George W. Bush in 2006. It is held twice a year in China and the United States in turn and has become an important platform for the economic leadership of the two countries to hold an in-depth exchange of views on the bilateral economic and trade relationship.

Chinese Vice Premier Wang Qishan, as special representative of President Hu, and US Secretary of Treasury Henry Paulson, as special representative of President Bush, co-chaired the two-day meeting.