The State Department Tuesday defended U.S. ambassador to Zimbabwe Christopher Dell, who is involved in a bitter verbal dispute with the government of President Robert Mugabe. Zimbabwean officials have said Mr. Dell might be expelled after his sharp criticism of the Mugabe government's economic policies.

The State Department says it stands by Ambassador Dell's blunt criticism of the Mugabe government, and it is suggesting that authorities in Harare are trying to make the American envoy a scapegoat for their own economic failures.

The already-difficult relationship between the United States and the Harare government has become even more strained since remarks by Ambassador Dell last week in which he accused Mr. Mugabe of "corrupt rule" and "gross mismanagement" of the country's economy.

Zimbabwean officials have said that Mr. Dell might be expelled and the country's state radio quoted President Mugabe as saying Tuesday the ambassador could "go to hell."

Asked about the reported remark at a news briefing, State Department Deputy Spokesman Adam Ereli said the dispute is not about comments by the American ambassador but rather the failed economic policies of the Mugabe government, which, he said, have produced soaring inflation and unemployment and caused Zimbabwe's annual economic output to shrink by 40 percent in the last five years.

"What Ambassador Dell is pointing to is the ruinous effects of these polices on the people of Zimbabwe and the standing of Zimbabwe," he said. "And what has happened is that they've gone after him personally, which is wrong and should be condemned, instead of examining what the true problem is, which, as I said, is failed policies and a consistent and unrelenting attack on I think the freedoms and initiatives of the Zimbabwean people."

Spokesman Ereli said Mr. Dell, like other U.S. ambassadors around the world, will continue to speak out frankly, and that the United States will not "shy away" from pressing Zimbabwe to adopt transparent, accountable economic policies that are the norm for the rest of the world, but which "Zimbabwe seems curiously blind to."

Mr. Ereli said Zimbabwean officials have not communicated any expulsion threat directly to Mr. Dell, but said the ambassador has been called to a meeting at the Zimbabwean foreign ministry Wednesday.

Last month, Mr. Dell was detained by Zimbabwean security agents as he walked into a restricted area of a botanical garden near President Mugabe's official residence in Harare. The State Department said Mr. Dell inadvertently entered the secure area, which was poorly marked, and that Zimbabwean officials apologized for the incident.

However government-owned Zimbabwean media accused the ambassador of deliberately provoking a diplomatic incident.

The Bush administration has been a persistent critic of Mr. Mugabe, who has ruled Zimbabwe for 25 years, for economic mismanagement and human rights violations including repression of dissent and election-rigging.

The United States imposed economic and travel sanctions against Mr. Mugabe and other government officials after he was re-elected president in disputed elections in 2002.

Those sanctions, similar to ones by the European Union, were widened last year to include several government-connected businesses.

Senior State Department officials have said in recent weeks the penalties might be further expanded in response to the controversial slum clearance program Mr. Mugabe launched in May, that has displaced hundreds of thousands of people.