Senate Majority Leader Mitch McConnell (R-Ky.) said Thursday he has "requested and received" the resignation of Senate Sergeant-at-Arms Michael Stenger.

Driving the news: Capitol Hill law enforcement and security have come under heavy criticism over their response to Wednesday's siege on the U.S. Capitol by supporters of President Trump.

• Authorities were overwhelmed by rioters who stormed the Capitol building and made their way into the Senate chamber, as well as some lawmakers' offices. At least four people have died following the siege, according to officials.
• Earlier Thursday, Senate Minority Leader Chuck Schumer (D-N.Y.) called for firing Stenger when Democrats take the majority in the upper chamber — if Stenger had not already resigned.

The big picture: House Sergeant at Arms Paul Irving has given his resignation notice, Speaker of the House Nancy Pelosi (D-Calif.) said Thursday.

• Capitol Police chief Steven Sund is also resigning, effective Jan. 16, a department spokesperson said.

What's next: Deputy Sergeant-at-Arms Jennifer Hemingway will serve as acting sergeant-at-arms, McConnell said in a statement.

• "I thank Jennifer in advance for her service as we begin to examine the serious failures that transpired yesterday and continue and strengthen our preparations for a safe and successful inauguration on January 20th," McConnell said.

Multiple lawmakers have also vowed to investigate law enforcement's response to Wednesday's violent U.S. Capitol breach.

Go deeper: Biden, activists decry "double standard" in police response to mob at U.S. Capitol