The Justice Department has asked a federal appeals court to impose tighter restrictions on the hundreds of lawyers who represent detainees at Guantánamo Bay, Cuba, and the request has become a central issue in a new legal battle over the administration’s detention policies.

Saying that visits by civilian lawyers and attorney-client mail have caused “intractable problems and threats to security at Guantánamo,” a Justice Department filing proposes new limits on the lawyers’ contact with their clients and access to evidence in their cases that would replace more expansive rules that have governed them since they began visiting Guantánamo detainees in large numbers in 2004.

The filing says the lawyers have caused unrest among the detainees and have improperly served as a conduit to the news media, assertions that have drawn angry responses from some of the lawyers.

The dispute is the latest and perhaps the most significant clash over the role of lawyers for the detainees. “There is no right on the part of counsel to access to detained aliens on a secure military base in a foreign country,” the Justice Department filing argued.