Only hours before Ecuador’s announcement, WikiLeaks charged that Secretary of State John Kerry quietly urged the Ecuadorean government, in a meeting late last month, to stop Mr. Assange from publishing the emails or interfering in the election. The State Department issued a statement declaring that the reports were untrue.

Ecuador’s action, experts inside and outside the United States government say, is not likely to slow the flow of leaked emails. Those emails are routed through servers around the globe, and if the United States wanted to shut them down covertly, that presumably would have happened years ago.

In fact, American officials have said, turning off the flow of WikiLeaks data is a legally complicated issue, especially if American citizens or American-based firms are involved. The Obama administration, they say, does not want to be accused of suppressing unwelcome speech — in the manner of the Russians and the Chinese.

Efforts to reach WikiLeaks on Tuesday were unsuccessful. A sometimes spokesman, Kristinn Hrafnsson, did not return messages, and a telephone message and an email message to Sunshine Press, which represents Mr. Assange, were also unanswered.

Mr. Assange has insisted he does not know the source of the WikiLeaks material, though he has made no secret of his distaste for Mrs. Clinton. The United States government has said that much of the hacking was the work of Russian intelligence and was part of a broad effort to influence the election. So far, the White House has not announced how it will respond, though several options have been discussed with President Obama, according to administration officials.

On Sunday, in a taped interview broadcast on NBC’s “Meet the Press,” Vice President Joseph R. Biden Jr., in what was either a warning or an effort at psychological warfare, said that “we’re sending a message” to the Russians “at a time and place of our choosing” and that President Vladimir V. Putin will “know it” when the message arrives. That seemed to suggest some kind of covert action, perhaps a cyberstrike, in retaliation for what the American intelligence community has described as a broad and unprecedented effort by a foreign power to influence American voters.

It is possible that Ecuador feared that, because of its decision to give exile to Mr. Assange, it risked becoming a witting or unwitting participant in an effort at voter manipulation.