Police arrested hundreds of pro-Palestinian protesters who were calling for a cease-fire in Gaza and an arms embargo on Israel at the Capitol on Tuesday, a day before Prime Minister Benjamin Netanyahu is set to deliver a controversial address to Congress.

More than 400 mostly Jewish protesters participated in a sit-in at the Cannon House Office Building’s rotunda wearing red shirts that read, “Jews Say Stop Arming Israel.” Footage showed rabbis leading the protesters in prayer and song while wearing shawls that said, “Never Again for Anyone.”

The demonstrators, organized by Jewish Voice for Peace, sang chants calling for a free Palestine and an end to genocide until Capitol Police arrived. Officers can be seen on video grabbing banners and arresting demonstrators before escorting them out.

“For nine months, we’ve watched in horror as the Israeli government has carried out a genocide, armed and funded by the U.S.,” JVP Executive Director Stefanie Fox said in a statement. “Congress and the Biden administration have the power to end this horror today.”

“Instead, our president is preparing to meet with Netanyahu and congressional leadership has honored him with an invitation to address Congress,” Fox continued. “Enough is enough. Biden and Congress must listen to the people: We need an arms embargo now to save lives.”

Tuesday’s arrests are likely a preview of bigger protests on Wednesday when Netanyahu addresses a joint session of Congress.

The Israeli prime minister is hoping to win more support for a military offensive that has devastated both Gaza and the occupied West Bank. He has so far refused to accept a cease-fire in exchange for the hostages kidnapped by Hamas in October.

The prime minister’s arrival has drawn the ire of politicians and civilians alike, who see the move as cozying up to a leader whose forces have killed more than 39,000 Palestinians in Gaza. Several major unions sent a letter to Biden on Tuesday demanding he stop funding Israel’s military offensive, and some have said they plan to mobilize in Washington on Wednesday to oppose Netanyahu’s visit.

Some Democratic lawmakers have already voiced their intent to boycott the prime minister’s speech — while House Speaker Mike Johnson (R-La.) has warned against protests during the proceedings.

“I commend the members who have refused to grant an audience to the man orchestrating an ongoing campaign of mass murder, starvation, and ethnic cleansing, and who has never missed an opportunity to defy and undermine their own president,” said former U.S. Army Maj. Harrison Mann, one of a dozen administration officials and diplomats who resigned in protest of the Biden administration’s role in the war.

“I encourage them to continue using their voices and their votes with urgency to suspend arms shipments, force Netanyahu to embrace a ceasefire, and restore humanitarian aid before famine and disease engulf all of Gaza, and the Israeli government drags us deeper into needless wars in the region,” he continued.

Mann will join Rep. Delia Ramirez (D-Ill.) in boycotting Netanyahu’s speech.

Normally, Vice President Kamala Harris would preside over the prime minister’s address, but her team has said that the vice president, who is now the presumptive Democratic presidential nominee and has been more publicly sympathetic toward Palestinians than the president, can’t attend Netanyahu’s speech due to a conflicting campaign event.

“For months, the majority of Democrats and Americans, including American Jews, have supported a lasting ceasefire and hostage deal between Israel and Hamas,” Lily Greenberg Call, who was the first Jewish political appointee to resign over Biden’s Gaza policy, wrote in The Guardian on Monday. “Harris must make clear that she supports using the U.S. government’s leverage to end the bloodshed and reunite families.”