U.S. officials are considering using visa restrictions to prevent Chinese hackers from attending the popular Defcon hacker conference in Las Vegas, as part of a broad effort to curb Chinese cyber espionage, a senior administration official said on Saturday.

The official said the U.S. government could use such visa restrictions and other measures to maintain pressure on  after the United States this week charged five Chinese military officers and accused them of hacking into U.S. nuclear, metal and solar companies to steal trade secrets.

 has denied the charges, saying the U.S. grand jury indictment was "made up" and would damage trust between the two nations.

U.S. officials are weighing a range of options if China doesn't begin to acknowledge and curb its corporate cyber espionage, said the official, who was not authorized to speak publicly.

"We've tried to have a constructive dialogue. The State Department and the Defense Department have traveled to China to share evidence of hacking by the (People's Liberation Army), but those types of interchanges have not sparked a lot of progress or reciprocity," said the official.

Monday's indictment was the first criminal hacking charge that the United States has filed against specific foreign officials, and follows a steady increase in public criticism and private confrontation, including at a summit last year between U.S. President Barack Obama and Chinese President Xi Jinping.

Federal prosecutors said the suspects targeted companies including Alcoa Inc, Allegheny Technologies Inc, United States Steel Corp, Toshiba Corp unit Westinghouse Electric Co, the U.S. subsidiary of SolarWorld AG, and a steel workers' union.

The Wall Street Journal reported late on Friday that U.S. options could include releasing additional evidence about how the hackers conducted their alleged operations, and imposing other  and financial restrictions on those indicted or people or organizations associated with them.

Some FBI officials also advocated working with companies under cyber siege to feed bad information to hackers, which could complicate and slow Chinese cyber espionage efforts, according to the Journal.

The Defcon hacking convention, which every year draws more than 15,000 hackers, researchers, corporate security experts and others to Las Vegas, last year asked U.S. officials to stay away after former contractor Edward Snowden revealed details of extensive surveillance by the National Security Agency.

This year's event is scheduled for August 7 -10.

Ten to 12 Chinese citizens were unexpectedly denied visas last week to attend a space and cyber conference hosted by the Space Foundation in Colorado this week, according to the conference organizers.

Speakers at the conference included James Clapper, the director of U.S. national intelligence, and other high-ranking intelligence agencies and military officials.

State Department spokeswoman Jen Psaki said visa applications were confidential, but cautioned against drawing connections between the visa denials and the Chinese indictments.