Paul Hill, 49, a former Presbyterian minister, was the first person in the US to be executed for anti-abortion violence, as clinics braced themselves for a violent backlash.

"Paul Hill is a dangerous psychopath," stated Marti McKenzie, the spokeswoman for James S Pendergraft, a doctor who runs clinics in Orlando, Ocala, Tampa and Fort Lauderdale. "The bottom line is that when you work in the industry you're aware those people are out there every single day."

Hill shot the doctor, John Britton, 69, and his bodyguard, James Barrett, 74, at the Ladies centre in Pensacola, Florida in July 1994.

He claimed the shooting amounted to "justifiable homicide". He was denounced by moderate anti-abortionists but embraced by hardliners called the Army of God. A website created by that group contains many messages of support: "By your fulfilling scripture, you indeed will be remembered," said one message writer called Judy.

Hill was executed by lethal injection yesterday at Florida state prison.

A father of an 18-year-old son, and daughters, age 15 and 13, Hill had told reporters in a jailhouse interview earlier this week that he was a martyr in the anti-abortion cause and that he hoped his death would inspire more clinic attacks.

But Hill's actions have split the anti-abortionists over how far they are willing to go to make their case.

The Reverend Ed Martin, of the anti-abortion group Rescue America, told the newspaper Orlando Sentinel: "It's wrong to take the life of an unborn child. But it is equally wrong to take the life of an abortionist or his worker."

Several Florida officials connected to the case received threatening letters last week, accompanied by rifle bullets. Opposition to his execution produced an unlikely alliance of rightwing anti-abortionits and liberals opposed to the death penalty.

"The sooner I am executed the sooner I am going to heaven," Hill said in his interview. "I expect a great reward in heaven. I am looking forward to glory. I don't feel remorse. More people should act as I have acted."

Using his right as a death row prisoner under Florida law to hold a press conference before his execution, Hill said on Tuesday: "I believe the state by executing me will be making me a martyr. I think I have some natural apprehension, but no, I'm not afraid."

Jeb Bush, the governor of Florida and brother of the US president, George Bush, said he had no intention of changing his mind over Hill's execution. "I'm not going to change the deeply held views that I have on [the death penalty] because others have deeply held views that disagree," he said.

Over the past decade there have been at least 10 attempts to kill doctors and others involved in abortion services in the US and Canada, according to the abortion federation. The most recent killing was in 1998 in Amherst, New York.