BOSTON - A 10-day-old Massachusetts law that restricted protesters from approaching women entering abortion clinics was declared unconstitutional Monday by a U.S. District Court judge.

Judge Edward F. Harrington said the law infringed on the free-speech rights of abortion protesters by forcing them to stay at least 18 feet away from the entrance of clinics where abortions are performed.

The Attorney General's Office said it has not yet decided if it will appeal the ruling, which rendered the law invalid.

The law creating the "buffer zone" was passed by the Legislature over the summer, and went into effect on Nov. 10. Lawmakers began pushing for the law after gunman John Salvi killed two female workers at two Brookline abortion clinics in 1994.

In his 11-page decision, Harrington said protesters who plan to peacefully spread the anti-abortion message deserve the right to do so.

"Pro-life advocates who firmly believe that abortion remains a grave moral evil must be given as equal an opportunity as their opponents to express ... their sincere message of respect for the sanctity of innocent human life," he wrote. "The First Amendment requires no less."

Attorney General spokeswoman Ann Donlan said her office has not yet decided when -- or if -- they will appeal the decision.

"The legislation was designed to promote the public safety of everyone involved," Donlan said. "We still firmly believe that the law accomplished that aim in a way that did not violate any person's constitutional rights."

Thomas M. Harvey, the attorney representing the three women who filed the lawsuit, said the law went too far in infringing on protesters' rights to discuss their beliefs.

"No one has a constitutional right not to feel uncomfortable," he said. "A sidewalk is a public forum, and people -- all people -- have the right to air their views."

Advocates of abortion rights said they were disappointed by the decision, but hopeful it would be overturned on appeal.

"We believe ultimately the law will be upheld as constitutional," said Melissa Kogut, head of the Massachusetts office of the National Abortion and Reproductive Rights Action League. "It is addressing an important issue here in Massachusetts, and is the right thing at the right time."

Harvey said the three "sidewalk counselors" who filed the suit believed the law was unfair because it exempted clinic employees, giving them an "unfair advantage" in approaching women entering a clinic.

"Within the zone, workers at the clinic were free to persuade or cajole women in if they were having second thoughts. But people on the other side were not," he said. "Under the law, a pro-life person couldn't even ask them to listen or read a pamphlet, and that was not right."

State Sen. Susan Fargo, D-Lincoln, one of the main sponsors of the law, said she would consider amending portions of the measure to meet some of those concerns -- as long as the bulk of the law could stay in place.

Still, she stood by efforts to provide women access to healthcare without engaging in confrontations at the doorstep.

"I do not believe the very soft limitations in this bill defeats anybody's right to free speech," she said. "What it does is prevent in-your-face harassment, and that's what we were trying to tone down."

Harvey said he expects the Attorney General's Office to appeal the decision. But he said he is confident the judge's ruling will be upheld.

"The judge's reasoning was solid," he said. "We're on the right side of this."

Buffer zones are not unique to Massachusetts. The law here is similar to one in Colorado that created a 100-foot buffer zone around all medical facilities.

That law also was challenged by anti-abortion protesters, but was upheld by the U.S. Supreme Court in June.