WASHINGTON — Protests were held in more than 30 cities, including Boston, over the weekend to protest President Trump’s refugee ban, and they continued after the executive order was partly lifted by federal courts.

In Washington Sunday, hundreds of demonstrators lined Pennsylvania Avenue outside the White House and packed Lafayette Square. Many held placards with messages like ‘‘Islamophobia is un-American.’’

“No hate! No fear! Refugees are welcome here!’’ some chanted.

At Dulles International Airport in Virginia, hundreds of peaceful demonstrators sang the national anthem and created a cheering gantlet for travelers emerging from customs. The crowd yelled ‘‘Let them in!’’ and ‘‘Welcome!’’ as passengers, including some from majority-Muslim countries, rolled their suitcases into the airport

‘‘My kids go to school with people from everywhere,’’ said Sasha Moreno, of Reston, Va., whose 6-year-old daughter drew a red Statue of Liberty along with the message: ‘‘Welcome to America.’’

Her daughter’s kindergarten class includes many students from Sudan, one of the countries targeted by Trump’s order, which has brought a sense of anxiety in her own family.

The idea that her daughter’s friends’ grandparents would be barred from visiting the United States just because of who they are is unacceptable, and she wants her children to know that’s not what America stands for, Moreno said.

‘‘There are lots of Muslim students at her school. Hearing this stuff going on is really confusing’’ to them, Moreno said.

At the Washington rally, Amira Hassan, 26, remembered the excitement when she flew into Kennedy International Airport with her family as a refugee from Somalia in 2001.

Hassan is graduate student in public administration and a naturalized citizen. Since the Sept. 11, 2001, attacks, she has watched the rise of Islamophobia as her family built a life in the United States, she said. ‘‘It’s hard not to feel terrified and angry and sad and heartbroken,’’ she said.

Protests erupted Saturday and Sunday across the nation:

■ Chicago:Demonstrators rallied at O'Hare International Airport. The Chicago Sun-Times reported protesters blocked vehicle traffic to the international terminal for a time. The newspaper said some arriving travelers joined the protest.

■ Dallas: Protesters who gathered at Dallas/Fort Worth International Airport on Saturday evening voiced their displeasure with Trump’s executive order. A crowd of a few dozen ballooned into hundreds of demonstrators who chanted ‘‘Set them free!’’ At times, cheers erupted as those who had been detained got released.

■ Denver: Dozens of people converged on Denver International to show support for refugees. In the main terminal, they sang ‘‘Refugees are welcome here.’’ Some held signs declaring their identity, such as Jew or Christian, and the phrase ‘‘I come in peace.’’

■ Los Angeles: About 300 people expressed their displeasure at Los Angeles International Airport Saturday night after holding a candlelight vigil.

■ New York: Cries of ‘‘Let them in!’’ rose from a crowd of more than 2,000 people at John F. Kennedy International Airport, where 12 refugees were detained Saturday.

■ Portland, Ore.: A protest by several dozen people in and around Portland International Airport briefly disrupted light rail service.

■ San Diego: As motorists honked support, demonstrators outside San Diego International Airport chanted ‘‘No hate, no fear, everyone is welcome here.’’

■ San Francisco: Hundreds blocked the street near San Francisco International Airport’s international terminal.

■ Seattle: About 3,000 protesters chanting ‘‘no hatred, no fear, immigrants are welcome here’’ gathered Saturday evening and continued demonstrating into Sunday.