Activists opposing Israel's war in Gaza and Washington's support for its Middle Eastern ally plan protests at the US Capitol on Wednesday to coincide with Israeli Prime Minister Benjamin Netanyahu's US visit this week.
Police expect a "large number of demonstrators" and were making additional security arrangements but said there were no known threats.
Netanyahu will be in Washington this week for a July 24 address to a joint session of the US Congress. He is expected to meet President Joe Biden.
Biden has recently supported talks for a ceasefire but has continued military support for Israel.
Israel's military campaign followed an Oct. 7 attack by Hamas, whose militants surged into Israel, killing 1,200 and taking around 250 hostages, according to Israeli figures.
A coalition of groups is expected to participate in the protests, among them ANSWER (an acronym for "Act Now to Stop War and End Racism"), women-led peace and human rights group CodePink, Palestinian groups such as Palestinian American Community Center and Jewish groups including Jewish Voice for Peace.
CodePink told Reuters organizers had arranged buses for human rights advocates to come to Washington from numerous states across the country.
US Capitol Police statement
"We anticipate a large number of demonstrators to show up," the US Capitol Police said. "Our plan includes adding more officers – including from several outside agencies."
A flyer urged the formation of a "People's Red Line around the Capitol building" on Wednesday, where demonstrators will criticize the US government for not drawing a "red line" in supporting Israel despite the war's death toll.
Around 230 anonymous Capitol Hill staffers from 122 offices signed a letter, made public last week, urging their bosses to either protest or boycott the July 24 address to Congress by Netanyahu against whom the International Criminal Court prosecutor's office recently requested an arrest warrant over alleged war crimes.
US protests since war erupted in Gaza have included marches, vigils and blocking of bridges and roads near train stations and airports in multiple cities along with encampments on college campuses.