Friday, when he returned to his Cambridge office at American Friends Services Committee, he phoned ahead to let his colleagues know he was being followed by four unmarked cars and a helicopter, all of which tailed him from his Fields Corner home.

“I told them to come outside,” Toure says. “I didn’t want people to think it was just my imagination.”

When Toure stopped his car midway down the one-way street where his office is located, his colleagues approached the officers with cameras in hand. The officers took evasive measures.

“Every time I got close to one, they screeched their tires and turned away,” said Jamie Bissonette, who attempted to photograph the officers.

Tuesday, Bissonette and representatives of the American Civil Liberties Union, Community Church of Boston and city councilors Felix Arroyo and Chuck Turner gathered in support of Toure, whom they said is being unfairly harassed by law enforcement.

“The government has been given extraordinary resources to combat terrorism and, just as we feared, they are using those resources against citizens on the weakest kind of outdated intelligence information,” said Carol Rose, executive director of the ACLU of Massachusetts. “The result is a chilling of peaceful political speech not only for those individuals who are targets of such investigations but also for the rest of the citizenry.”

Last Friday the Boston Herald reported that Toure was identified by New York City police as one of two “notorious Boston Terrorists,” under their surveillance. Toure and others at the American Friends Service Committee say they neither attended nor planned to attend the protests in New York during this week’s Republican National Convention.

Toure says he does not know which law enforcement agencies are actually tailing him. When approached, the officers have refused to speak. ACLU Legal Director John Reinstein fired off a letter to the FBI’s Washington and Boston offices Tuesday demanding to know whether the agency has been involved in Toure’s surveillance.

The Boston office could not be reached for comment by the Banner’s press deadline.

Toure, a long time community activist, was convicted of gun possession and sedition in 1981. Since his release in 1992, he has worked on prisoners’ rights issues. He has been arrested in non-violent protests twice in recent years. In each case, charges were dropped.

Toure says the surveillance over the last week has been uncomfortable.

“It’s stressful to have someone watching your every movement,” he said. “I have to have someone with me all the time as a witness. You never know what’s going to happen.”