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Abortion clinics around the country are bracing for attacks after Olympic bomber Eric Rudolph (search) issued his manifesto justifying the use of violence to stop "the worst massacre in human history."

"When one of these extremists puts out a call to action, oftentimes, others do try to follow in their footsteps," said Vicki Saporta, head of the National Abortion Federation (search), which represents 400 U.S. clinics. "He clearly is speaking to the extremists who believe in justifiable homicide."

Rudolph will get four life sentences without parole after pleading guilty Wednesday to carrying out the deadly bombing at the 1996 Atlanta Olympics (search) and attacks at two abortion clinics and a gay nightclub. The blasts killed two people and wounded 123.

A federal prosecutor said Thursday she'll recommend that a $1 million reward go to two men who tracked Rudolph moments after the last deadly blast, and who provided authorities with a license plate number eventually traced to Rudolph's pickup truck.

In an 11-page manifesto handed out by his attorneys, Rudolph said the Olympic bombing was an attempt to embarrass the United States in front of the world for allowing abortion (search).

"Because I believe that abortion is murder, I also believe that force is justified ... in an attempt to stop it," Rudolph wrote.

Abortion clinics and federal agents are on a heightened state of alert.

"We're making sure our liaisons have kept up with the clinics and to make sure the security clinics have is up to date," said Mike Campbell, spokesman for the Bureau of Alcohol, Tobacco, Firearms and Explosives. "Most of them are very cognizant they can be a target of anybody who doesn't like abortion."

Anti-abortion groups condemned Rudolph's endorsement of violence.

"It looks to me as if he views himself as a one-man army against the entire world or at least the United States," said Troy Newman, president of Operation Rescue (search). "I would concur with his opinion that abortion is murder. However, his frustration that leads to violence is never an acceptable way to accept this."

U.S. Attorney Alice Martin's recommendation on the $1 million reward will be forwarded to the FBI, but the final decision is up to Attorney General Alberto Gonzales (search).

"The witnesses have made no request for a reward, and it's not available until the prosecution has been completed," Martin said. "But in my opinion it is worthy of recommendation that those two witnesses be considered."

Martin said Jermaine Hughes, a 20-year-old college student at the time, and attorney Jeff Tickal provided the key evidence that led to Rudolph's quick identification after a fatal abortion clinic bombing in Alabama.

After the explosion, Hughes alerted police that he had seen a suspicious figure walking away from the clinic. He and Tickal then both followed Rudolph briefly in separate vehicles.

Tickal wrote down the license number of Rudolph's pickup truck and eventually provided the first eyewitness identification of Rudolph based on a newspaper photo.

After that, Rudolph spent more than five years as a fugitive before he was captured in 2003 in Murphy, N.C.