President Donald Trump reportedly told the pregnant widow of a U.S. soldier who died last week in Niger that he "knew what he signed up for ... but when it happens, it hurts anyway."

U.S. Rep. Frederica Wilson, D-Fla., told a local news outlet that Trump made the remark during a five-minute phone call to Myeshia Johnson, widow of U.S. Army Sgt. La David Johnson.

Johnson was among four service members who died last week in northwestern Africa during an ambush.

Wilson said the president told the widow that the slain soldier “knew what he signed up for ... but when it happens, it hurts anyway.”

"Yes, he said it," Wilson told Local 10 News. "It's so insensitive. He should have not have said that. He shouldn't have said it."

A top White House adviser told the station that the president's conversations "with the families of American heroes who have made the ultimate sacrifice are private."

Trump called Johnson’s widow to offer condolences. Myeshia, who is expecting their third baby in January, is also left to take care of their 2-year-old son and 6-year-old daughter following the death of her husband.

Sgt. Johnson died during a Green Berets mission in Niger. Islamic militants ambushed the soldiers Oct. 4 with machine guns and grenades.

Trump was criticized for lack of focus on the deadly attack, although the Department of Defense reportedly launched an investigation into the ambush, the New York Daily News reported.

The president said last week that he planned to call the families of the fallen soldiers to express sympathy. "I will, at some point, during the period of time, call the parents and the families, because I have done that, traditionally," he told reporters.

The three other slain service members were: Staff Sgt. Bryan C. Black, 35, of Puyallup, Wash.; Staff Sgt. Jeremiah W. Johnson, 39, of Springboro, Ohio; and Staff Sgt. Dustin M. Wright, 29, of Lyons, Ga.

The Associated Press contributed to this report.