Colin Kaepernick anthem row

Speaking in China, Mr Obama said the player had raised legitimate issues.

Mr Kaepernick stirred controversy when he sat during the national anthem to protest against racial injustice.

Some players have followed his example and sat or kneeled through the anthem.

Asked about the issue during a news conference at the G20 in Hangzhou, President Obama said it was tough for those in the military to understand why Mr Kaepernick might snub the national anthem.

But he said he did not doubt his sincerity to raise issues.

The San Francisco 49er's quarterback stayed seated as The Star-Spangled Banner played in a pre-game ceremony in protest against what he called the oppression of black people in the US.

The gesture has provoked a huge reaction, with some applauding him as principled, others seeing him as disrespectful and unpatriotic. Here are some of the key responses.

#VeteransForKaepernick rally behind athlete

An often-repeated criticism of Kaepernick has been that his actions are offensive to members of the US military.