SAN FRANCISCO (Reuters) - A U.S. District Court on Wednesday dismissed lawsuits against telecommunications companies in a warrantless wiretap case, ruling that former President George W. Bush's administration had properly requested the cases closed for national security reasons.

Companies including AT&T Inc and Verizon Communications Inc faced dozens of suits accusing them of improper participation in a warrantless wiretap program launched by Bush after the September 11 attacks.

In 2008, the Democratic-led Congress retroactively shielded phone companies from such suits, on the basis that immunity was needed to win future wiretap cooperation.

He ruled that former U.S. Attorney General Michael Mukasey had certified properly that the cases fell under the immunity standards of the Foreign Intelligence Surveillance Act Amendments Act of 2008.