Almost seven years after Occupy Wall Street spawned encampments across the US to protest against economic inequality, activists are borrowing the same title and method to create a series of Occupy Ice camps in protest against the government’s immigration policies.

The first Occupy Ice camp popped up outside the Immigration and Customs Enforcement office in Portland, Oregon, on Sunday 17 June. Since then, camps have been set up in Philadelphia, San Diego, San Francisco and elsewhere.

Unlike the first Occupy Wall Street occupation, which took over Zuccotti Park in lower Manhattan after months of planning, the Occupy Ice camp in Portland was unplanned.

“There was a vigil being held to honor people who have suffered from these policies,” said Whitney Handrich, one of the activists involved in Portland.

“After that vigil, people just started talking and thinking of ways about how we can do more. Some decided to stay, and it snowballed after that.”

On that first Sunday, five people spent the night under an open-sided gazebo; two nights later, there were 29 tents set up outside the Ice building, close to the Willamette river. Handrich, a 30-year-old nanny and yoga teacher, estimates that after a week more than 50 tents were in the camp.

“This was definitely spontaneous,” Handrich said. “But people have passed down knowledge from Occupy Wall Street, so that, I think, helps. So some of the lessons from that organization have been learned to make this more sustainable.”

A common criticism of the first iteration of Occupy was that protesters were big on energy but low on specific demands or goals. Occupy Ice Portland’s ultimate aim, like that of other Occupy Ice groups, is simply to abolish Ice. But shorter-term goals include making sure Portland city council lives up to its commitment to be a sanctuary city and offering legal help and resources to undocumented immigrants.

The group’s presence forced the Ice building to close for more than a week in June. In the process of federal law enforcement agents reopening the building on 23 June, eight protesters were arrested.

By then, though, activists elsewhere had begun to take note. On 2 July, a camp appeared outside an Ice office in Philadelphia. More than 20 people were arrested there on Tuesday – police and homeland security officers told protesters they couldn’t block Ice’s garage doors. On Thursday afternoon, police forcibly dismantled the camp, the Philadelphia Inquirer reported.

As some camps are removed, other occupations are springing up, including in traditionally less-Democratic states. On Monday, a group of 20 people pitched their tents outside the Ice office in Louisville, Kentucky, and they plan to stay there indefinitely.

Anti-Ice protesters in Portland. Photograph: John Rudoff/Sipa USA/Rex/Shutterstock

“We had been reading about Occupy Ice and watching the news like everyone else,” said Jesús Ibáñez, who is part of Occupy Ice Louisville. “We didn’t have any contact with Portland before we set up.”

The lack of centralized control is reminiscent of the Occupy Wall Street movement, which began with the New York City camp and led to Occupy rallies taking place in more than 900 cities across 82 countries.

Ibáñez and his group set up camp directly outside the Ice building, barricading the front and rear entrances to the building in the process. Within 45 minutes, officials from homeland security had dismantled the camp, ordering Ibáñez and the others to leave federal land. The activists set up their tents a few yards back, on city-owned land, and have no plans to leave.

“We plan on staying on there as long as it stays to abolish Ice,” Ibáñez said. “We’re in this for the long haul.”

Ibáñez, 33, wasn’t part of the Occupy movement in 2011, but he said a couple of others in the Louisville camp had been involved and had shared their experiences. Although the Louisville Occupy Ice branch did not communicate with the existing camps before setting up, Ibáñez said they had since been in contact with camps in Tacoma, Washington, and the original Portland camp.

“They’ve been telling us what works for them, what doesn’t work for them,” Ibáñez said. “How to interact with counter-protesters, things like that.”

Hardrich said that in Portland, people had stood near the camp holding pro-Trump signs, and someone had thrown feces at some of the tents. It hasn’t deterred the occupiers, however – just as the people taking part in New York City’s Occupy Ice demonstration haven’t been deterred by being unable to pitch tents.

“We have sleeping bags, blankets, pillows and yoga mats,” said Abby Rojas, who has been camping at Foley Square, in lower Manhattan, since last week. Rojas, 24, and about 15 others established their demonstration after reading about Occupy Ice Portland. They chose Foley Square for its proximity to the courts that hear deportation cases.

“In NYC, our occupation is focused on getting resources to any immigrant families, like food, medicine, legal work. We’re just trying to help out as much as we can,” Rojas said.

Rojas said she felt the Occupy Ice movement was growing – “and it’s a very positive sign that its growing” – but she wanted to make sure people retained their focus.

“It takes more than taping a ‘we welcome refugees’ poster to your window,” Rojas said.