England's Football Association will investigate the booing by fans of players taking a knee at games at Millwall and Colchester at the weekend, the governing body said in a statement on Monday.

Players in England have been taking a knee before matches since June in support of the 'Black Lives Matter' movement, which spread around the world following protests over the death of George Floyd while in police custody in Minneapolis in May.

The Premier League and Football League have since linked the kneeling gesture to their own anti-racism campaigns, including "No Room for Racism".

"The FA can confirm that investigations are underway into crowd-related incidents at both The Den and JobServe Community Stadium on Saturday 5 December 2020," the governing body said.

"Observations have been sought from all of the relevant parties and they will have until Thursday Dec. 10 2020 to provide their respective responses."

Millwall's official fan club has said supporters who booed players before its match at home to Derby County were not motivated by racism.