Republican presidential contender Donald Trump, who has ignited a firestorm over comments on immigrants in recent weeks, seized on the case of a random killing in San Francisco, calling the fatal shooting “another example of why we must secure our border immediately.”

Trump, talking Saturday to Fox and Friends, expressed surprise over the strong backlash to his comments about Mexican immigrants and crime, saying he has become “sort of a whipping post for bringing it up.”

The real estate magnate also blasted fellow GOP presidential candidates who have criticized him for his blunt talk.

On Twitter, Trump expressed his “heartfelt condolences” to the family of Kathryn Steinle, who was shot in the chest and killed Wednesday evening in what police said was a random shooting. Trump also said he had spoken to the victim’s brother.

Francisco Sanchez, 45, has been charged with killing the 32-year-old woman who was hit while strolling with her family along the scenic Embarcadero waterfront.

Police said there appeared to be no previous connection between the victim and the suspect, who never exchanged words with Steinle before opening fire.

The killing quickly became a national political issue after federal and state officials noted Sanchez is a convicted felon who has been deported numerous times.

Gillian Christensen, spokesperson for U.S. Immigration and Customs Enforcement (ICE), said Friday the suspect had been previously deported five times, most recently in 2009, and had a criminal history that included seven prior felony convictions, including four narcotics charges.

Christensen said ICE turned him over to the San Francisco Police Department in March “on an outstanding drug warrant.” ICE officials requested that they be informed whenever the suspect was set to be released, but “the detainer was not honored.”

Trump said in a statement Friday that the “senseless and totally preventable act of violence committed by an illegal immigrant is yet another example of why we must secure our border immediately.”

On Twitter, Trump said, “Where are the other candidates now that this tragic murder has taken place b/c of our unsafe border. We need a wall!”

On Saturday, Trump spoke out again, telling Fox and Friends that immigrant crime is out of control that he is “sort of a whipping post for bringing it up.”

“People don’t want to talk about it, and if you talk about it, you’re a racist,” Trump said.

In announcing his presidential bid last month, Trump triggered a backlash, particularly in the Hispanic community, after warning that the U.S. is becoming a “dumping ground” for the world’s problems.

“When Mexico sends its people, they’re not sending their best,” he said last month in announcing his candidacy. “They’re sending people that have lots of problems … they’re bringing drugs, they’re bringing crime. They’re rapists. And some, I assume, are good people.”

Univision and NBC responded by canceling plans to broadcast the Miss USA and Miss Universe pageants, which Trump owns. Macy’s dropped his products from its stores and NASCAR announced that it would no longer hold its end-of-season awards ceremony at a Trump hotel in Miami.

Trump said on Fox and Friends that he was taken aback by the strong, negative reaction. “I didn’t know it was going to be quite this severe,” he said. “But I really knew it was going to be bad.”

Trump also said he was “quite surprised” by NASCAR’s move “because these are people who want to stop illegal immigration, they want to stop crime.”

Some fellow Republicans have also criticized Trump, including presidential contender Sen. Marco Rubio, of Florida, who called Trump’s remarks “not just offensive and inaccurate, but also divisive.” Former Republican Gov. George Pataki of New York has also criticized Trump over the issue.

On Saturday, Trump dismissed Pataki as a “failed governor” and said Rubio was “very weak on immigration.”