Texas and at least two other states said Friday that they have shot down requests from Russian officials to watch voters at polling stations.

A U.S. State Department spokesman called the requests — also made of Louisiana and Oklahoma — "nothing more than a PR stunt."

Letters obtained by The Texas Tribune show that Russia's consul-general in Houston, Alexander K. Zakharov, said his nation wanted to study "the U.S. experience in organization of voting process."

In his response last month, Texas' secretary of state, Carlos H. Cascos, wrote that "only persons authorized by law may be inside of a polling location during voting."

"We are unable to accommodate your request to visit a polling station; however, our office is available to discuss generally the election process or perhaps facilitate a meeting with local election officials," he wrote.

A spokeswoman for Cascos, Alicia Pierce, told the Tribune that no such meeting was ever set up.

There is a formal process for foreign governments to observe American elections, though states are free to approve or deny those requests, State Department spokesman Mark Toner said Friday.

Russia has not participated in an international mission to observe elections, so its effort to do so on the state level represents "nothing more than a PR stunt," Toner said.

Donald Trump, the Republican nominee for president, has suggested multiple times that the election could be "rigged" against him; his call for supporters to monitor polling places has led to worries about voter intimidation.

Trump has also called for the country to "find the 30,000 emails that are missing" from Democrat Hillary Clinton's private server and been criticized for his public praise of Russia's President Vladimir Putin.

Do you think Putin will be going to The Miss Universe Pageant in November in Moscow - if so, will he become my new best friend? — Donald J. Trump (@realDonaldTrump) June 19, 2013

Meanwhile, U.S. intelligence agencies have accused Russia of hacking the emails that Wikileaks has published to tarnish Clinton's campaign. Russia has denied those charges.

White House Press Secretary Josh Earnest said Friday that the purpose of Russia's poll-watching requests was unknown, adding that it was "appropriate" for people to be suspicious of its motives.

Zakharov's office has not responded to calls seeking comment.

The Associated Press contributed to this report.