The files were posted to a blog used by Guccifer 2.0, which at least one cybersecurity firm has labeled an operation of Russian security services

The hacker Guccifer 2.0 posted phone numbers, email addresses and passwords for nearly 200 sitting and former Democratic lawmakers on Friday, including current members of intelligence and armed services committees.

The files were posted to a blog used by the hacker, which at least one cybersecurity firm has labeled an operation of Russian security services. Intelligence officials, other firms and Democrats have also accused operatives supported by the Russian government of hacking the Democratic National Committee this year.

The files include contact information for 193 current and former members of Congress, including House minority leader Nancy Pelosi, and dozens of details for members of their staffs. The hacker also posted mundane campaign documents with summaries of various candidates supported and opposed by the party.

The documents came from a hack of the Democratic Congressional Campaign Committee, the hacker said, including a claim that they showed how “the US presidential elections are becoming a farce, a big political performance where the voters are far from playing the leading role”.

Spokespeople for the Democratic National Committee did not immediately respond to requests for comment.

The Wall Street Journal verified the contact information for Representative Steny Hoyer, whom it called on his cellphone. “This is sensitive information and it could be used in a very detrimental way by a foreign government,” Hoyer told the paper.

He suggested “offensive measures” in response to the hack, echoing a letter by Representative Adam Schiff and Senator Dianne Feinstein last month. “If Russia made the material available,” they wrote to the White House, “then the episode would represent an unprecedented attempt to meddle in American domestic politics – one that would demand a response by the United States.”

The publication of documents from the Democratic party is the second this year and another jarring new precedent in an election year, following the release of 20,000 emails by Wikileaks last month.

Those emails suggested bias by some members of the Democratic party against Senator Bernie Sanders and in support of Hillary Clinton, and their release led to the resignation of the Democratic National Committee’s chairwoman, Debbie Wasserman Schultz.