A Minneapolis police officer accused of pressing his knee against George Floyd's neck was charged with a more serious charge of second-degree murder on Wednesday, and for the first time charges were levelled against three other officers, issuing warrants for their arrests, even as protests continued across the US.

An updated criminal complaint against Derek Chauvin says his actions were a "substantial causal factor in Mr. Floyd losing consciousness, constituting substantial bodily harm, and Mr. Floyd's death as well." The unintentional second-degree murder count carries a maximum penalty of 40 years in jail. The complaints against the others accuse them of aiding and abetting Chauvin's actions and of manslaughter.