Defying the federal government's ban on most travel to Cuba, about 80 people crossed back into the United States at the Peace Bridge on Saturday after a two-week trip to the island nation.
They were greeted by about a dozen supporters and a small band as they walked across the border plaza and into Front Park.
Most were members of the Venceremos Brigade, which has been pushing for more normal relations with Cuba since 1969.
"It's an immoral blockade," said Tshaka Barrows, 30, an Oakland, Calif., resident who was among the brigade members returning from Cuba. "There's no justification for what they're doing."
The U.S. government imposed travel and trade restrictions on Cuba four years after Fidel Castro came to power there in 1959, and has largely maintained them since.
The first group of about 15 members walked over the bridge around 10 a.m. and groups of 10 to 15 each continued to cross into the afternoon.
Molly Doherty, an attorney who works with Venceremos, said once the travelers acknowledge to government border agents that they were in Cuba, they are released. Many are later sent a letter advising them they are being fined $7,500, if it is their first trip, or more.
But Doherty said members always appeal. So far, she said, no hearings have been held and no fines have been collected.
U.S. citizens are not barred from traveling to Cuba but, unless permitted, are prohibited from doing business with Cubans, including spending money traveling to, from or within the country.