Mr. Aloko’s office on Wednesday released a statement to news organizations — not including The Times — that accused Mr. Rosenberg of writing an “article that is considered divisive and contrary to the national interest, security and stability of Afghanistan.” The statement said the “attorney general decided that Matthew Rosenberg should leave the country within the next 24 hours, and he will not be allowed to re-enter the country.”

The statement suggested that Mr. Rosenberg, 40, had presented his opinion in the article while “falsely attributing it to high-level government officials.” The article was based on high-ranking Afghan government sources, some of whom spoke on the condition of anonymity because of fears of prosecution for sedition if their names were used, as Mr. Rosenberg noted in the article.

A statement issued by the office of President Hamid Karzai, while not mentioning the expulsion, quoted the president as telling the head of the United Nations here, Jan Kubis, that a recent article in The New York Times “showed foreign interference and conspiracy in order to destabilize Afghanistan.”

“This kind of article should not be allowed,” the statement read.

Mr. Aloko’s own statement did not specify what, if any, laws had been broken, or what legal grounds there might be for such an expulsion, which is unprecedented in the 13 years of the government of Mr. Karzai.

The attorney general’s statement said the decision had been made because Mr. Rosenberg “didn’t cooperate well during the interrogations” carried out by the attorney general’s office on Tuesday.