SAN JOSE, Calif. - Online search engine leader Google Inc. vowed to fight legal efforts by the federal government seeking to force the company to turn over closely guarded search results as part of an investigation into online pornography.

The company has so far refused to comply with a subpoena issued last year for a broad range of material from its databases, including a request for one million random Web addresses and records of all Google searches from any one-week period, lawyers for the U.S. Justice Department argued in court papers filed Wednesday in federal court in San Jose.

The government contends it needs the data to determine how often pornography shows up in online searches as part of an effort to revive an Internet child protection law that was struck down two years ago by the U.S. Supreme Court.

The Child Online Protection Act was intended to punish online pornography sites that make their content accessible to minors.

The government is preparing to defend the law in a federal court in Pennsylvania on the basis that it is more effective than software filters in protecting children from porn.

The Mountain View-based company said it opposes releasing the information because it would violate the privacy rights of its users and would reveal company trade secrets.

Nicole Wong, an associate general counsel for Google, said the company will fight the government's efforts "vigorously."

"Google is not a party to this lawsuit, and the demand for the information is overreaching," Wong said.