Donald Trump said fellow GOP rivals don't have "the guts to even talk about" immigration and its effect on crime, punching back at other candidates such as Sen. Marco Rubio who have denounced his contentious comments on immigration.

Trump pointed to a San Francisco tourist allegedly shot by an illegal immigrant as evidence that his comments that Mexicans are bringing crime, drugs and rapists across the border was spot on.

"Our Southern border is unsecure. I am the only one that can fix it, nobody else has the guts to even talk about it," Trump said on Twitter.

He was referring to the shooting death of Kathryn Steinle, a tourist who was allegedly shot by an illegal immigrant who was allegedly deported five times.

In his Twitter tirade Trump took aim at Florda Sen. Marco Rubio, who called Trump's immigration comments "not just offensive and inaccurate, but also divisive."

He asked Rubio what he would say to the family of Kathryn Steinle "who was viciously killed b/c we can't secure our border? Stand up for US."

Former New York Gov. George Pataki has called on all GOP candidates to denounce Trump's comments.

Trump took aim at both Rubio and Pataki during an interview on "Fox & Friends" recently where he said Rubio has been "weak" on immigration and that Pataki was a horrible governor who is polling at zero now.