SEATTLE (AP) — A federal judge has struck down a Washington state law aimed at battling online sex trafficking after an internet advocacy group filed a lawsuit challenging the measure's constitutionality.

Judge Ricardo Martinez's order was filed Thursday in Seattle after the state declined to continue arguing in court over Engrossed Senate Bill 6252, which was one of several measures combating online sex trafficking and aimed at online classified site Backpage.com written by lawmakers earlier this year.

Gov. Chris Gregoire signed the bill into law in March.

But the Electronic Frontier Foundation sued on behalf of Internet Archive, arguing that targeting Internet service providers was unconstitutional and violated federal law. They argued the new law's language was "vague" and threatened web hosts and online libraries.

A message to the state Attorney General's office was not immediately returned.