(Reuters) - A California federal judge has dismissed a lawsuit alleging that Alphabet Inc's Google and a host of other companies unlawfully collected data from children who watched videos on online video-sharing platform YouTube and targeted advertisements to them.

U.S. District Judge Beth Labson Freeman in San Jose held in a Monday ruling that the plaintiffs' privacy claims under state law are "expressly preempted" by the federal Children's Online Privacy Protection Act, granting the companies' motion to dismiss.

The plaintiffs, a group of parents of minor children, were given leave to further amend their complaint.

A lawyer for the plaintiffs from Silver Golub and Teitell didn't immediately respond to a request for comment. A lawyer at Hogan Lovells representing Google referred a request for comment to the company, which didn't immediately respond.

The plaintiffs claimed the companies invaded the privacy rights and reasonable expectation of privacy of millions of kids under the age of 13 by "surreptitiously and deceptively" gathering their personal information, including persistent identifiers, without verifiable parental consent. That allowed Google and YouTube to gain advertising revenue from the monetized channels operated by the other companies, which include The Cartoon Network Inc, DreamWorks Animation LLC, Mattel Inc and several others, the lawsuit alleged.

The claims under various states' laws are premised on violations of COPPA, the 1998 federal law that imposes requirements of certain operators of websites and online services.

The companies argued in a bid to dismiss an amended complaint that COPPA's preemption clause "expressly and impliedly" preempts the state law claims.

Private individuals can't directly sue under COPPA - the U.S. Federal Trade Commission and state attorneys general can enforce the law. And Congress included an express preemption clause "specifically to foreclose actions like this one that attempt to use state law to sidestep COPPA's enforcement mechanism," the companies argued.

Separately, the alleged conduct has already been addressed through an FTC and New York Attorney General enforcement action against Google and YouTube in 2019 that resulted in a $170 million settlement, the companies said.

The plaintiffs shot back that the companies' express preemption argument is "contrary to the statutory text of COPPA, which carefully limits preemption only to state law claims 'inconsistent' with COPPA." The implied preemption argument also fails because the companies didn't show that the application of the state laws are an "obstacle" to COPPA enforcement, the plaintiffs said.

The court on Monday sided with the companies. The judge agreed with their characterization that although styled as coming out of state law, the claims are predicated on COPPA violations rather than activity that "independently violates state law."

The plain text of the law's preemption clause indicates Congress' wish to preempt the claims, the judge said, adding that the plaintiffs' reading of the clause to only preempt "inconsistent" state laws is incomplete.

"This Court agrees that allowing Plaintiffs to sue for violations of COPPA under state law runs afoul of COPPA's express preemption clause due to the inconsistency with the remedial scheme that assigns enforcement of COPPA to the FTC and state attorneys general," the judge said.

The judge left the door open for the plaintiffs to amend the complaint to plead facts showing the conduct goes beyond just a violation of COPPA.

The case is Hubbard et al v. Google LLC et al, U.S. District Court for the Northern District of California, No. 19-cv-07016-BLF

For the plaintiffs: Silver Golub and Teitell and Pritzker Levine

For the companies: Hogan Lovells for Google and YouTube; Bigson, Dunn & Crutcher for Cartoon Network; ZwillGen for DreamWorks; Frankfurt Kurnit Klein Selz for Hasbro; Munger, Tolles & Olson for Mattel; Jacobson, Russell, Saltz & Fingerman for Remka; Venable for Pocketwatch