WASHINGTON — House Minority Leader Nancy Pelosi urged Speaker Paul Ryan on Tuesday to keep Republican candidates from using hacked Democratic documents in this year’s election campaigns, the latest political twist in a summer of revelations of digital break-ins believed linked to Russia.

“Russia’s cyber attack is an unprecedented assault on the sanctity of our democratic process,” Pelosi, D-Calif., wrote in a letter to the Wisconsin Republican. “We must come together to say that defending our democracy from Russia’s meddling is more important than any advantage or disadvantage in this election.”

A GOP aide said Ryan cannot control campaign ads by Republican committees that by law are barred from consulting with the party’s candidates.

Pelosi’s letter came as Congress returned from summer recess just two months from an Election Day in which Democrats hope to gain sizable numbers of House seats, as well as capture the Senate and retain the White House.

Democrats have been happy to link Russia to Donald Trump’s GOP presidential candidacy, highlighting his July plea that Russia help find Democratic rival Hillary Clinton’s missing emails and work former campaign manager Paul Manafort did for a pro-Russian party in Ukraine. Trump later said his call that Russia find Clinton’s emails was sarcastic.

Federal officials have been investigating electronic break-ins into Democratic Party computers by people that private cybersecurity analysts have blamed on Russian intelligence agencies. That’s included a breach of the Democratic Congressional Campaign Committee, House Democrats’ campaign arm.

Embarrassing internal Democratic documents have been posted online. Rep. Debbie Wasserman Schultz of Florida relinquished her post as Democratic Party chief in July after the documents showed the organization tilting toward Clinton in her campaign against Vermont Sen. Bernie Sanders for the presidential nomination.

“Democrats and Republicans must present a united front in the face of Russia’s attempts to tamper with the will of the American people,” Pelosi wrote.

Ryan spokeswoman AshLee Strong steered a reporter seeking comment to the National Republican Congressional Committee, which runs House GOP campaign efforts.

NRCC spokeswoman Katie Martin said Ryan and NRCC chief Rep. Greg Walden, R-Ore., do not “have control over” campaign ads produced by an arm of that committee, which is legally required to spend money without consulting candidates.

Martin cited an NRCC digital ad attacking a Democratic candidate for Congress in Florida, using information a hacker posted online and that Democrats have called “unverified documents provided by the Russians.” Democrats have complained about the GOP’s use of that information.