House GOP probes of the Secret Service’s handling of the attempted assassination of former President Trump have quickly grown tense.

One House committee has accused the Department of Homeland Security (DHS), which oversees the Secret Service, of “unprofessionalism” following uncertainty about an agreed-upon member briefing — and is pledging a subpoena.

And Republicans have taken aim at Secret Service Director Kimberly Cheatle directly, with Rep. Lauren Boebert (Colo.) leading a bill filed Monday to defund her salary and House Majority Leader Steve Scalise (La.) on Tuesday becoming the highest-ranking member to say she should step down. 

“I think she should,” Scalise said at a CNN-Politico event at the Republican National Convention in Milwaukee when asked if Cheatle should step down. “I’ve been very disappointed in her and her lack of candor.”

Cheatle told ABC News on Monday that she would not resign.

The congressional investigations started cordially enough, with the House Oversight and Accountability Committee announcing Monday that Cheatle had agreed to appear at a hearing a week later.

A House Homeland Security Committee aide said that Chair Mark Green (R-Tenn.) spoke to Cheatle on Sunday following the shooting and received a commitment that requested documents about the security plans for the Butler, Pa., rally would be provided promptly.

But while the Homeland Security Committee majority had planned to have the Secret Service director brief members Monday, the agency later asked to reschedule a meeting, according to a panel spokesperson.

The Oversight Committee had separately planned to hold a member briefing with the Secret Service on Tuesday. But in a blistering statement Tuesday afternoon, a committee spokesperson said that DHS had taken over communications for the Secret Service and then refused to confirm a briefing time.

“The Oversight Committee has a long record of bipartisan oversight of the Secret Service, and the unprofessionalism we are witnessing from current DHS leadership is unacceptable,” the spokesperson said.

And in an attempt to “head off any attempt by DHS to backtrack” on Cheatle’s appearance in Monday’s committee hearing, Oversight Chair James Comer (R-Ky.) will issue a subpoena for her to attend, the spokesperson said. They added: “Director Cheatle must answer to Congress and the American people about the historic failure that occurred on her watch.”

Asked about the Oversight spokesperson’s accusations and whether Cheatle would accept a separate invitation to appear at the Homeland Security panel’s July 23 hearing, the Secret Service referred The Hill to DHS. A DHS spokesperson told The Hill regarding the hearing that it “responds to congressional requests directly via official channels, and the Department will continue to respond appropriately to Congressional oversight.”

A Homeland Security Committee aide had said earlier that the Secret Service and DHS “have not even acknowledged receipt of our testimony request let alone given us an answer on if they will attend our Tuesday hearing.”  

Despite the Oversight panel frustrations, an alternative briefing plan appears to be in the works.

The FBI and DHS were considering setting up a phone meeting with all House members for Wednesday to discuss the assassination attempt, according to a congressional source familiar with the plans. It was unclear if that impacted the DHS’s handling of the previously agreed-upon hearing with the Oversight panel.

In a statement Monday, Cheatle said that the Secret Service will “work with the appropriate Congressional committees on any oversight action.”

The House Oversight and Homeland Security panels are just two of the at least six committees in both the House and Senate involved in a flurry of briefings and investigations in the aftermath of the Saturday shooting that left Trump with an injured ear, one rally attendee dead and two others injured.

And scrutiny is increasing in those other areas of Congress as well.

Sen. Chuck Grassley (R-Iowa) on Tuesday sent a letter to the DHS inspector general’s office asking for a full investigation of the assassination attempt.

“The lack of information from DHS, [Secret Service], and the FBI is unacceptable. They owe Congress and the American people full and complete transparency on how this tragedy could possibly occur,” Grassley wrote in his letter.

And Rep. Jim Himes (Conn.), the top Democrat on the House Intelligence Committee who was part of an FBI briefing Monday on the assassination attempt, called for as much transparency into the matter as possible.

“At moments like this, in the absence of factual information, it is easy for conspiracy theories to take hold,” Himes said in a statement Tuesday. “During the briefing, I requested that the FBI share as much information publicly as they are able without compromising their investigation. I believe the same is true of the Secret Service’s review to determine what failures allowed this attack to occur. We owe that transparency to the American people as the investigation continues.”