Obama urges persistence in fighting racism

US President Barack Obama said banishing racism in the United States can only happen incrementally, and urged young people to "be persistent" in fighting bias.

He was speaking as protests continue in cities across the United States, where thousands have gathered over the past two weeks to condemn a spate of killings of black suspects by white police.

"This isn't going to be solved overnight, this is something that is deeply rooted in our society, it's deeply rooted in our history," Obama said in an interview with Black Entertainment Television that was aired last night.

He urged young people to press on in their fight against racism, and said patience was crucial.

"We have to be persistent, because typically progress is in steps, it's in increments," he said.

"When you're dealing with something as deeply rooted as racism, or bias, in any society, you've got to have vigilance but you have to recognize that it's going to take some time."

He said race relations had improved over the last 50 years, even though tensions persist.