SAN FRANCISCO (Reuters) – U.S. Defense Secretary Ash Carter on Tuesday warned China against what he called “aggressive” actions in the South China Sea region, including the placement of surface-to-air missiles on a disputed island, and said they would have consequences.

“China must not pursue militarization in the South China Sea,” Carter said in a wide-ranging speech at the Commonwealth Club in San Francisco. “Specific actions will have specific consequences.”

He did not elaborate, but underscored the U.S. military’s determination to safeguard maritime security around the world, and particularly in the South China Sea region, which sees about 30 percent of the world’s trade transit its waters each year.

The U.S. defense chief also took aim at both Russia and China for their actions to limit Internet access, as well as state-sponsored cyber threats, cyber espionage and cyber crime.

In his prepared remarks, Carter drew a sharp contrast between such behavior by Russia and China and what he described as much healthier U.S. actions to preserve Internet freedom.

“We don’t desire conflict with either country,” he said. “But we also cannot blind ourselves to their apparent goals and actions.”

He urged cooperation with U.S. technology companies to ensure data security and necessary encryption levels, despite growing controversy over the FBI’s request to circumvent security features on an iPhone used by one of the San Bernardino, California, shooters.

Carter, on his third visit to the technology-heavy Silicon Valley since taking office a year ago, said he could not address the case specifically since it was under litigation, but made clear that the Defense Department viewed encryption as a necessary part of data security.

“It’s important to take a step back here, because future policy shouldn’t be driven by any one particular case,” Carter said in what appeared to be a departure from the Justice Department’s view.

Carter noted that the Defense Department is the largest user of encryption in the world and needed it to be as strong as possible.

(Reporting by Andrea Shalal; Editing by Mohammad Zargham)