WASHINGTON — The United States and China ended two days of high-level economic talks yesterday, agreeing to negotiate a new investment treaty and expand cooperation on energy projects.

Treasury Secretary Henry Paulson hailed the modest outcome as "creating a foundation" for future gains. The head of the Chinese delegation, Vice Premier Wang Qishan, labeled the talks "highly successful."

Briefing reporters, the officials said they agreed to begin negotiating a bilateral investment treaty like those the U.S. maintains with several other countries. Such treaties give investors protection against having their assets seized, including the right to appeal disputes to an international arbitration panel.

The two sides have been holding preliminary discussions on such a treaty for 17 months, though no deal is expected before the November election. And Rep. Charles Rangel, D-N.Y., chairman of the House Ways and Means Committee, wrote Paulson citing "serious concerns" over a potential accord, given Chinese trade practices that have swollen the U.S. trade deficit.