Baghdad, Iraq ? Without firing a shot, U.S. and British forces stormed a house Thursday and freed three Christian peace activists who were bound but unguarded, ending a four-month hostage ordeal that saw an American in the group killed and dumped along a railroad track.

The U.S. ambassador and the top American military spokesman held out hope that the operation on the outskirts of Baghdad could lead to a break in the captivity of American reporter Jill Carroll, a freelance writer for The Christian Science Monitor who was abducted Jan. 7.

The military spokesman, Maj. Gen. Rick Lynch, said the 8 a.m. rescue of the Briton and two Canadians from a “kidnapping cell” was based on information divulged by a man during interrogation only three hours earlier. The man was captured by U.S. forces on Wednesday night.

A senior Iraqi military officer told The Associated Press, however, that the operation had been under way for two days in the Abu Ghraib suburb west of Baghdad, site of the notorious prison. The officer, who spoke on condition of anonymity because of the sensitivity of his position, said U.S. and British forces refused to give him other details.

Canadian Prime Minister Stephen Harper said Canadian forces also took part in the rescue operation, although their precise role was unclear.

No kidnappers were present when the troops broke into the house where the peace activists were discovered with their hands tied.

“They were bound, they were together, there were no kidnappers in the areas,” Lynch said at a news briefing.

The freed men were Canadians James Loney, 41, and Harmeet Singh Sooden, 32, and Briton Norman Kember, 74. The men – members of the Chicago-based Christian Peacemaker Teams – were kidnapped Nov. 26 along with an American colleague, Tom Fox, 54.

Fox’s body was found this month, shot and dumped in western Baghdad.

“We remember with tears Tom Fox,” group co-director Doug Pritchard said in Toronto. “We had longed for the day when all four men would be released together. Our gladness today is bittersweet by the fact that Tom is not alive to join his colleagues in the celebration.”