Animal-rights activists whose protests spurred the Salt Lake City Council this week to enact a ban on targeted residential picketing say their demonstrations will continue, one way or another, and they may sue the city.

Jason Rose of the Utah Primate Freedom Project and others, including some council members, worry that the ordinance may infringe on residents' free-speech rights.

"We're considering our options — whether to sue before being arrested or be arrested and then sue," Rose said Thursday. "Any abridgment on freedom of speech you have to be very careful with. It's the First Amendment — not the second or third or fourth, not that those are any less important — but this is the first."

The group has protested in front of the homes of University of Utah researchers since 2005 in opposition to research involving animals. At the request of Mayor Rocky Anderson's administration, the City Council on Tuesday voted 5-2 to ban demonstrations within 100 feet of a residence when the protest is aimed at someone living there.

"It's really an anti-harassment issue, not a free-speech issue," said Councilman Dave Buhler, a mayoral candidate who voted in favor of the ordinance. "Nobody's saying you can't say whatever you want."

But Councilman S�ren Simonsen, who voted against the new ordinance, said Thursday that he has lingering concerns about it.

"There are some free-speech issues," he said.

Before the vote, Anderson's chief of staff, Sam Guevara, wrote in a letter to the council that city attorneys are confident the ban is constitutionally sound because it imposes regulations on the time, place and manner of protests rather than banning them. He cited a 1988 U.S. Supreme Court ruling that upheld a similar ordinance in Brookfield, Wis.

But Simonsen also questions whether the new rule will have unintended consequences, including sending protesters down the street.

"All that we've done with this ordinance is we've said, 'You can't protest within 100 feet of this house,' which just pushes people beyond the 100-foot line and may create more of a problem for the neighbors," he said.

Council members approved the ordinance after a closed-door session with their attorneys. Such sessions are permitted under state law as part of attorney-client privilege. But Simonsen said there were a number of issues raised in that meeting that went unresolved, and he was surprised by the vote, which he believed could have been postponed to a later meeting.

Rose agreed that the ordinance passed more quickly than his group expected, leaving them unsure of their next move. But he said he sees a court battle ahead.