California police arrested a woman who threw a feminine hygiene device containing “what appeared to be blood” onto the floor of the state Senate, splashing onto lawmakers and forcing them to finish their work in a committee room on the final day of the legislative session.

The protesters were watching the Senate from the upstairs balcony, according to multiple lawmakers, when a woman hurled a red liquid that landed on senators’ desks and yelled about "dead babies".

The incident comes after dozens of protesters filled the Capitol to demonstrate against a new law that seeks to curb the fraudulent issuance of medical exemptions for vaccinations. Gov. Gavin Newsom signed the bill into law earlier this week, according to the Associated Press.

State Sen. Steve Glazer who called the Senate floor a "crime scene," posted a photo on Twitter of the item that was thrown, saying: "Senators Galgiani, Hurtado, Skinner, Mitchell, Rubio and me were all hit by red liquid thrown from the Senate gallery. I'm told a person has been arrested. Senate in recess."

The tweet was later deleted.

In a video posted by twitter user @connectwithdeb, a woman audibly yells "that's for the dead babies" followed by gasps. At the end of the video, it shows a woman surrounded by authorities saying "Those babies blood is on your hands... my blood is on the floor of the Senate."

Authorities were trying to determine whether the liquid was blood, according to the San Francisco Chronicle.

In a statement, Senate President pro-Temp Toni G. Atkins said that there would be "open doors" within California’s legislative process for those "who wish to observe or speak out on a variety of issues, but we cannot allow anyone to endanger others," and that what happened in the Senate Chamber was "unacceptable."

"We will continue to do the people’s important business,” Atkins concluded.

Sen. Scott Wiener wrote on Twitter: “A few minutes ago, the anti-vaxxer stalkers - who’ve engaged in a harassment campaign all week— dropped a red substance onto the Senate floor from the elevated public gallery, dousing several of my colleagues.”

“The person who committed this assault screamed it was baby blood. These anti-vaxxers are engaging in criminal behavior. They’ve now repeatedly assaulted senators and are engaging in harassing and intimidating behavior every single day, as we try to do the people’s work. They’re a cancer on the body politic and are attacking democracy,” he continued.

“I took an oath to give the Valley a voice, that includes fighting for policies that represent the diversity of my region which has been neglected,” state Sen. Melissa Hurtardo wrote in a tweet. “No one said the fight would be easy. Todays event was an unacceptable example of the challenges we face. As always, we’ll rise above.”

Contributing: Associated Press and Shane Newell from the Desert Sun