"To the best of my knowledge, I think I've called every family of somebody that's died, and it's the hardest call to make," Trump told Fox News Radio host Brian Kilmeade. "As far as other representatives, I don't know, I mean you could ask Gen. Kelly, did he get a call from Obama?"
"I don't know what Obama's policy was," he added. "I write letters, and I also call."
Kelly's son, Marine 2nd Lt. Robert Kelly, was killed in Afghanistan in 2010. A White House official confirmed to The Hill that John Kelly did not receive a call from Obama at the time.
The president's comments came after he said during a news conference on Monday that most other presidents, including Obama, did not call the families of fallen service members.
Trump's claim came in response to a question about why he had not spoken publicly about the killings of four Army Green Berets in Niger earlier this month. The president said that he had written letters to the soldiers' families and would call them soon.
“If you look at President Obama and other presidents, most of them didn’t make calls,” he said. “A lot of them didn’t make calls. I like to call when it’s appropriate.”
Pressed on his claim, Trump said he was "told" Obama did not often call, but acknowledged that the former president "probably did sometimes."
Obama and other presidents have held phone calls and meetings with families of fallen soldiers, and Trump's comment was heavily criticized by former staffers in the Obama administration.
--This report was updated at 12:00 p.m.