WASHINGTON — Intelligence officials told lawmakers behind closed doors on Tuesday that Russia was not directly supporting any candidates as it tried to interfere in the presidential race, an assertion that contradicted an earlier briefing and prompted accusations from Democrats that the Trump administration was politicizing intelligence.

“The I.C. has not concluded that the Kremlin is directly aiding any candidate’s re-election or any other candidates’ election,” an unclassified summary given to lawmakers said, using shorthand for the intelligence community. “Nor have we concluded that the Russians will definitely choose to try to do so in 2020.”

Speaker Nancy Pelosi challenged the officials during the first of two briefings on Tuesday, saying their assertions differed from a classified hearing last month where a top election security official discussed Russia’s preference for President Trump’s re-election, according to three people present for Tuesday’s session. The previous briefing drew angry responses from House Republicans.

Mr. Trump attacked the briefings earlier in the day, accusing Representative Adam B. Schiff, Democrat of California and the chairman of the House Intelligence Committee, of dwelling too much on Russian election interference. “There is another Russia, Russia, Russia meeting today,” Mr. Trump wrote on Twitter. “It is headed up by corrupt politician Adam ‘Shifty’ Schiff, so I wouldn’t expect too much!”