WASHINGTON • The pregnant widow of an American soldier killed in an ambush in Niger said President Donald Trump struggled to remember his name during a condolence call, in an account Mr Trump immediately disputed.

Mr Trump's call to Ms Myeshia Johnson, whose husband Sergeant La David Johnson was one of four US soldiers killed in the Oct 4 militant attack, has generated a storm of controversy and comes as questions swirl over how the attack happened.

"Yes, the President said that he knew what he signed up for but it hurts anyways," Mrs Johnson said on ABC's Good Morning America TV programme on Monday, in her first public comments on the death of her 25-year-old husband.

"It made me cry because I was very angry at the tone of his voice and how he said it."

Ms Johnson, who is carrying the couple's third child, said she "heard him stumbling on trying to remember my husband's name and that hurt me the most".

Mr Trump fired back on Twitter, insisting: "I had a very respectful conversation with the widow of Sergeant La David Johnson, and spoke his name from beginning, without hesitation!"

Details of Mr Trump's call were made public last week by a Democratic congresswoman who claimed the President had offended Sgt Johnson's widow, drawing accusations from the White House of politicising the issue.

The escalating row, now heading into its second week, prompted Mr Trump's chief of staff John Kelly, a former general whose son died in Afghanistan, to deliver an emotive defence of the President - while lashing out at the Florida congresswoman, Ms Frederica Wilson.

Ms Johnson told ABC that Ms Wilson's account of the call was "100 per cent correct", saying she was a lifelong family friend and had listened in over a speakerphone.

AGENCE FRANCE-PRESSE