The FBI pushed Thursday for more built-in backdoors for online communication, but beat a hasty retreat from its earlier proposal to require providers of encrypted communications services to include a backdoor for law enforcement wiretaps.

FBI general counsel Valerie Caproni told Congress that new ways of communicating online could cause problems for law enforcement officials, but categorically stated that the bureau is no longer pushing to force companies like RIM, which offers encrypted e-mail for business and government customers, to engineer holes in their systems so the FBI can see the...