The effort to pressure Ukraine for political help provoked a heated confrontation inside the White House last summer that so alarmed John R. Bolton, then the national security adviser, that he told an aide to alert White House lawyers, House investigators were told on Monday.

Bolton got into a tense exchange on July 10 with Gordon D. Sondland, the Trump donor turned ambassador to the EU, who was working with Rudolph W. Giuliani, the President’s personal lawyer, to press Ukraine to investigate Democrats, according to three people who heard the testimony.

The aide, Fiona Hill, testified that Bolton told her to notify the chief lawyer for the National Security Council about a rogue effort by Sondland, Giuliani and Mick Mulvaney, the acting White House chief of staff, according to the people familiar with the testimony.

“I am not part of whatever drug deal Sondland and Mulvaney are cooking up,” Bolton, a Yale-trained lawyer, told Hill to tell White House lawyers, according to two people at the deposition. (Another person in the room initially said Bolton referred to Giuliani and Mulvaney, but two others said he cited Sondland.)

It was not the first time Bolton expressed grave concerns to Hill about the campaign being run by Giuliani. “Giuliani’s a hand grenade who’s going to blow everybody up,” Hill quoted Bolton as saying during an earlier conversation.

The testimony revealed in a powerful way just how divisive Giuliani’s efforts to extract damaging information about Democrats from Ukraine on President Trump’s behalf were within the White House.

Hill, the senior director for European and Russian affairs, testified that Giuliani and his allies circumvented the usual national security process to run their own foreign policy efforts, leaving the President’s official advisers aware of the rogue operation yet powerless to stop it.

At one point, she confronted Sondland, who had inserted himself into dealings with Ukraine even though it was not part of his official portfolio, according to the people informed about Hill’s testimony.

He told her that he was in charge of Ukraine, a moment she compared to secretary of state Alexander M. Haig Jr’s declaration that he was in charge after the Ronald Reagan assassination attempt, according to those who heard the testimony.

According to whom, she asked. The President, he answered.