The Oakland Police Department's strip-search policy is unconstitutional because it provides too low a threshold for officers seeking to check for contraband on suspects in public places, a federal judge said in a ruling made public Friday.

Under a department policy implemented in 2004, officers are allowed to search people if they have a "reasonable suspicion" to believe the people are hiding something illegal, such as drugs, or would destroy or ingest it unless it was immediately recovered.

But attorneys for a group of men claiming they were wrongfully searched said the policy is unconstitutional because the standard is lower than that of probable cause, the standard police must meet before arresting someone.

U.S. District Judge Marilyn Hall Patel agreed.

"While reasonable suspicion is adequate to justify a strip search in the context of a detention facility when institutional security is a concern ... it is insufficient to justify a strip search in the field," Patel wrote. The police policy "is unconstitutional to the extent that it allows strip searches of any kind in the field to be performed on less than probable cause."