BEIJING  The Chinese premier Wen Jiabao expressed concern on Friday about the safety of China’s $1 trillion investment in American government debt, the world’s largest such holding, and urged the Obama administration to provide assurances that its investment would keep its value in the face of a global financial crisis.

Speaking at a news conference at the end of the Chinese parliament’s annual session, Mr. Wen said he was “worried” about China’s holdings of Treasury bonds and other debt, and that China was watching United States economic developments closely.

“President Obama and his new government have adopted a series of measures to deal with the financial crisis. We have expectations as to the effects of these measures,” Mr. Wen said. “We have lent a huge amount of money to the U.S. Of course we are concerned about the safety of our assets. To be honest, I am definitely a little worried.”

He called on the United States to “maintain its good credit, to honor its promises and to guarantee the safety of China’s assets.”