Protesters clashed outside the offices of key swing vote lawmakers after the Senate voted Friday to advance Brett Kavanaugh's Supreme Court nomination.

Demonstrations have swamped Capitol Hill throughout the Kavanaugh confirmation process.

Key undecided senators -- as well as congressional leaders -- have been receiving the majority of the protests, in particular key remaining undecided senators Republican Susan Collins of Maine and Democrat Joe Manchin of West Virginia.

The protests have been a consistent reminder of the political pressures lawmakers face and have been a constant occurrence along side Kavanaugh's nomination, which has been rocked by an allegation of sexual assault and accusations of inappropriate sexual behavior. Kavanaugh has denied all allegations against him.

According to a Capitol Hill police officer, authorities are investigating a female protester allegedly assaulting a man outside Collins' office, and two people have been detained and are currently being questioned. Police do not know the extent of the alleged assault, according to the officer.

Groups of female protesters and pro-Kavanaugh women clashed outside Collins' office following Friday's vote, while the Maine lawmaker remains one of two key undecided senators.

As a group of about 20 Kavanaugh supporters went into Collins' office, a few protesters shouted at them from outside. Women from both sides, standing a few feet away from each other, shouted "shame" right in each others' faces — across the doorway of Collins' office.

Another group of protesters occupying Manchin's office had tense but peaceful arguments with some Kavanaugh supporters.

At one point, Kavanaugh supporters took a selfie in front of the placard marking Manchin's office. Protesters then mockingly took a selfie with the Kavanaugh supporters behind them.

Protesters at Arizona Sen. Jeff Flake's office alternated between chants of "are we survivors," "shame," and "stop Kavanaugh," wearing shirts that said "Be a hero" and "Believe women." Capitol police officers gave them two warnings before telling them to disperse or risk arrest. Flake told MSNBC that he would support Kavanaugh's nomination barring a last-minute development.

Before the vote Friday morning, protesters gathered outside the home of Senate Majority Leader Mitch McConnell and staged a "confirmation kegger," in the final hours before the Senate prepares for a confirmation vote for Brett Kavanaugh's embattled nomination to the Supreme Court.

Bearing cans of Pabst Blue Ribbon beer, signs with Kavanaugh's fraternity letters DKE, sunglasses and straw hats, the protesters sang "what do we do with a drunken justice early in the morning" and "what do we do with a confirmation early in the morning" to the tune of the sea shanty "What shall we do with a drunken sailor," followed by chants of "chug."

The protest was one of many throughout the week. Protesters marching arm in arm from the Supreme Court to Senate office buildings Thursday wore shirts that said "Believe women" while chanting "Hey hey! Ho ho! Kavanaugh has got to go!"

Some carried elaborate signs reading "KavaNOPE," "We believe survivors," and that the judge was "unfit to serve." One woman made a poster showing Sen. Jeff Flake's recent encounter in a Senate elevator with a protestor who demanded that Flake "look at" her.

Comedian Amy Schumer and model-actress Emily Ratajkowski were among the more than 300 people arrested at various protests on Capitol Hill on Thursday while senators reviewed the FBI report on the investigation into the allegations against Kavanaugh. The two were arrested at a US Senate building, where protesters chanted "believe survivors."

Before Kavanaugh's committee confirmation hearing last month, a group from the liberal advocacy group Demand Justice donned the red robes and white bonnets of the namesake handmaids in "The Handmaid's Tale," the Margaret Atwood book and Hulu TV series while protesting in the Hart Senate Building atrium. Others chanted "Save Roe, vote no."