WASHINGTON — An intelligence contractor was charged with sending a classified report about Russia’s interference in the 2016 election to the news media, the Justice Department announced Monday, the first criminal leak case under President Trump.

The case showed the department’s willingness to crack down on leaks, as Mr. Trump has called for in complaining that they are undermining his administration. His grievances have contributed to a sometimes tense relationship with the intelligence agencies he now oversees.

The Justice Department announced the case against the contractor, Reality Leigh Winner, 25, about an hour after the national-security news outlet The Intercept published the apparent document, a May 5 intelligence report from the National Security Agency.

The report described two cyberattacks by Russia’s military intelligence unit, the G.R.U. — one in August against a company that sells voter registration-related software and another, a few days before the election, against 122 local election officials.