The Republican National Committee paid to generate thousands of calls to the congressional offices of nearly three dozen House Democrats in recent weeks, an effort that was aimed at both shaping opinion around the impeachment inquiry and tying up the phone lines of the elected officials, according to two people briefed on the effort.

The calls were part of a broader effort by Republicans to influence public opinion around the investigation into President Trump. The Trump campaign and the Republican committee have taken the lead on political messaging defending Mr. Trump at a moment of political vulnerability, using television and digital ads, as well as the phone calls.

The fact that the calls to congressional offices, estimated to number 11,000, were partly intended to jam the phone lines of House Democrats — potentially thwarting access to government offices — was described at a recent dinner of more than a dozen Republican aides, advisers and elected officials, known as the “Off the Record” dinner. Officials with the Republican National Committee told others at the dinner about the calls, suggesting they were automated and indicating that the aim was to tie up the phones in Democratic offices, according to two people briefed on what was said.

Asked about the calls, Republican committee officials said they were not prerecorded “robocalls.” The officials said the committee used a vendor to survey voters. Those voters who said they opposed the impeachment inquiry were given the option of being connected to their congressional representative’s office, the officials said.