Washington ? More needs to be done to ensure the anonymity of federal air marshals, according to a critical new report Congress will look into this week.

The draft report, “Plane Clothes: Lack of Anonymity at the Federal Air Marshal Service Compromises Aviation and National Security,” cites the service’s dress code, which is supposed to prevent marshals from drawing attention to themselves.

In practice, the report found, “many federal air marshals indicate that the dress code actually draws more attention to the identity of the federal air marshals because of its rigid requirements that prevent federal air marshals from actually blending in with their surroundings.”

The report also faults the service for requiring marshals to stay at designated hotels and show their credentials upon checking in.

And the report raised questions about boarding procedures by marshals, expressing concern that these procedures could give away the marshals’ identity.