US President Donald Trump talks to reporters on the South Lawn of the White House as he boards Marine One on October 26, 2018 in Washington, DC. - Trump is traveling to North Carolina for a 'Make America Great Again' rally.

President Donald Trump on Friday said he does not plan to call the two former presidents Barack Obama and Bill Clinton, who were targeted with pipe bombs this week.

Speaking on the South Lawn as he prepared to depart for a campaign rally, Trump was asked if he planned to reach out to the two former presidents.

"If they wanted me to, but I think we'll probably pass," Trump said.

The comment came after authorities arrested Florida resident Cesar Sayoc on Friday and charged him with crimes related to 13 pipe bombs that were mailed to prominent Democrats and public figures who have been critical of Trump.

To be sure, Trump is not required to call the two former presidents. But there is a long tradition of civility and communication among U.S. presidents and former presidents. Trump has largely eschewed this tradition, however.