WASHINGTON, D.C. — Thousands of people gathered in the nation's capital Saturday afternoon to call for a cease-fire in Gaza, marking 100 days since Israel launched its military operation following the Oct. 7 attack on Israel by Hamas. 

A sea of red and green Palestinian flags covered Freedom Plaza, just east of the White House, as marchers convened in downtown Washington, D.C., to protest Israel's ongoing military operation that has left over 23,000 people dead and more at risk of starvation and disease in the small Palestinian territory of 2.3 million people.

Demonstrators unfurled a giant Palestinian flag across the center of the square. Many in the crowd wore keffiyehs, traditional black and white Palestinian scarves.

Some demonstrators held signs reading “End the war on Gaza” and “Let Gaza Live.” Other signs criticized U.S. support of Israel and President Joe Biden, with messages such as, “End all U.S. aid to Israel.”

Several Palestinian Americans spoke to the crowd of the devastating toll the Israel siege of Gaza had taken on their families.

“President Biden has my family’s blood on his hands,” said Alaa Hussein Ali, of Michigan, whose brother was killed as he tried to evacuate to southern Gaza with his pregnant wife and children.

In addition, Ali said he lost 100 family members, including over 60 children, and half were buried under rubble from Israeli air strikes.

A group of marchers pressed to the center of the crowd, chanting “From the river to the sea, Palestine will be free” to a drum beat, as others joined in.

On Thursday, U.S. and U.K.-backed attacks on Houthi rebels in Yemen in response to attacks on ships in the Red Sea threatened an escalation in the region.

The Council on American-Islamic Relations (CAIR) issued an urgent call to action after the attack on sites in Yemen. The council, an organizer of the march, said the Biden administration's decision to fire on the rebel group without congressional approval risks a "regional war."

"This president is unnecessarily, illegally and dangerously risking the loss of more innocent lives – including the lives of Americans – for the sake of the genocidal Israeli government, all without approval from Congress," CAIR National Executive Director Nihad Awad said in a press release on Thursday.

CAIR is one of more than 200 organizations nationwide supporting the march, according to the American Muslim Task Force on Palestine, a coalition of Muslim advocacy organizations.

"Our demand is simple," National Deputy Director of the Council on American-Islamic Relations Edward Ahmed Mitchell told USA TODAY. "Stop the violence, secure a cease-fire, secure the release of all hostages and all political prisoners, and then resume efforts to secure a just and lasting peace by ending the occupation."

The march falls two days before Martin Luther King Jr. Day and draws inspiration from "Dr. King's legacy of speaking out against the Vietnam War and rallying other Americans do the same," Mitchell said.

Gaza death toll grows as South Africa accuses Israel of genocide

The march came as the death toll from Israel's ongoing military operation in the Gaza Strip climbed past 23,000 and South Africa presented its case to the U.N.'s top criminal court on Thursday accusing Israel of engaging in genocide against Palestinians in the region. Some South African flags could be seen in the crowd at Freedom Plaza on Saturday.

"Israel has a genocidal intent against the Palestinians in Gaza," Tembeka Ngcukaitobi, an attorney representing South Africa, told the International Court of Justice. "The intent to destroy Gaza has been nurtured at the highest level of state."

Israel defended itself in counter arguments on Friday, with representative Tal Becker calling South Africa's case a "profoundly distorted factual and legal picture."

"The entirety of its case hinges on a deliberately curated decontextualized and manipulative description of the reality of current hostilities," Becker said.

The situation has become increasingly dire in the Gaza Strip as humanitarian aid organizations struggle to deliver supplies to the war-ravaged population. The U.N.'s Office for the Coordination of Humanitarian Affairs said on Thursday that only three out of 21 deliveries of food, medicines, water, and other lifesaving items had reached northern Gaza in ten days due to "excessive delays" and denials of passage at Israeli checkpoints.

U.S. Secretary of State Antony Blinken also urged Israel to minimize civilian death in its military operations in meetings with Israeli Prime Minister Benjamin Netanyahu, President Isaac Herzog and other leaders in Tel Aviv on Tuesday. He also pressed Israel to support a Palestinian state in order to ease relations with other countries in the region.

"These goals are attainable, but only if they’re pursued together. This crisis has clarified you can’t have one without the other," he said.