US President Biden has angrily criticised an investigation into his handling of classified files which questioned his memory.

He held a surprise news briefing on Thursday evening, telling reporters: "My memory is fine."

Mr Biden confronted a claim that he struggled to remember when his son died, saying,"How the hell dare he raise that?"

Special Counsel Robert Hur decided not to charge Mr Biden for mishandling files.

But his report made several scathing remarks, including suggesting the president's memory had "significant limitations".

It said that it would be difficult to convict the president of improper handling of files because "at trial, Mr Biden would likely present himself to a jury, as he did during our interview of him, as a sympathetic, well-meaning, elderly man with a poor memory".

Mr Biden responded that despite his age, he was the most qualified person to be president.

Referring to interviews he gave the special counsel late last year, he said: "I was very occupied. I was in the middle of handling an international crisis," - referring to the 7 October attacks by Hamas in Israel which occurred a day before.

Mr Biden's age has become a top concern for voters going into November's presidential election.

Asked to comment on the latest developments in the Gaza war during Thursday's evening news conference, he confused the presidents of Mexico and Egypt.

"I think as you know initially, the president of Mexico, Sisi, did not want to open up the gate to allow humanitarian material to get in. I talked to him. I convinced him," he said.