In an escalation of the confrontation between the United States attorney in Manhattan, Preet Bharara, and Gov. Andrew M. Cuomo over the governor’s cancellation of his own anticorruption commission, Mr. Bharara has threatened to investigate the Cuomo administration for possible obstruction of justice or witness tampering.

The warning, in a sharply worded letter from Mr. Bharara’s office, came after several members of the panel issued public statements defending the governor’s handling of the panel, known as the Moreland Commission, which Mr. Cuomo created last year with promises of cleaning up corruption in state politics but shut down abruptly in March.

Mr. Bharara’s office has been investigating the shutdown of the commission, and pursuing its unfinished corruption cases, since April.

In the letter, sent late Wednesday afternoon to a lawyer for the panel, prosecutors alluded to a number of statements made by its members on Monday, which generally defended Mr. Cuomo’s handling of the commission. The statements were released on the same day Mr. Cuomo first publicly responded to a report in The New York Times that described how he and his aides had compromised the commission’s work.