U.S. Rep. Jared Polis said during a tour of the Islamic Center of Fort Collins that, if President-elect Donald Trump were to establish a registry targeting Muslims, he would declare Islam as his faith.

Polis, a Democrat whose district includes Fort Collins, said during the Tuesday tour that he was very worried about "some form of registry," and pledged "I will join you and I know many other Americans will join you."

Polis, who is Jewish, said it would be an act of civil disobedience.

Trump supported a registry for immigrants from Muslim countries while on the campaign trail, according to USA TODAY. Concerns about a religion-based registry led many tech companies to say they would refuse to help with its creation.

"(Trump) made a point of attacking Muslim Americans on the basis of faith," Polis told the group of Fort Collins Muslim leaders.

Tawfik AboEllail, president of the Islamic Center of Fort Collins, said there are concerns that the Trump administration might try to create World War II-style internment camps for Muslims and asked about that possibility. Polis said the chances of those camps or a registry passing both Congressional scrutiny and Constitutional muster were "extremely low." But that could change with another terrorist attack linked to Muslims.

"We need to remain watchful," he said.

AboEllail said the Islamic Center faced a protester, who chanted threatening things at children heading to a Sunday worship service, last winter. He described his congregation as "shocked" when Trump won the presidency.

"My wife was in tears," he said. "So many people are so concerned about what happens next."

He said the Islamic Center won't back down against discrimination against Muslims and would peacefully challenge any such policies. He noted in an interview that the center has an open-door policy for people wanting to learn more about the center or Islam. AboEllail commended Polis for his outreach to the community and called him "a representative for all."

Polis also offered help for those in the Muslim community seeking visas to return to the United States after trips home to certain countries. As it stands now, they are issued "one-way" visas, members of the center said. Nadya Ashwish, who is a native of Libya, said she feared she wouldn't be able to return to Fort Collins after traveling to Libya to care for her mother, who had cancer. Ashwish's husband and children live here with her and she is studying at Colorado State University.

As the principal of the Islamic and Arabic School at the center, Hana Gatlawi, put it, "we're stuck here."

Polis said his office is able to help people navigate the return visas process. The phone number for his Fort Collins office is 970-226-1239.

This story has been updated for clarity: Polis' office can only help people with the visa process.