Sport in the US has ground to a halt after the Milwaukee Bucks called off their fixture in protest at the shooting of Jacob Blake.

Blake, a black man, was shot seven times in the back by police on Sunday in Kenosha, Wisconsin near Milwaukee.

Following the incident, which sparked protests and scenes of violence in the US, the NBA postponed three play-off games while, in baseball, three MLB games were called off after teams decided not to play. Five Major League Soccer games have also been postponed.

After calling off their game against the Orlando Magic, the Bucks players released a statement that said: "Despite the overwhelming plea for change, there has been no action, so our focus today cannot be on basketball.

"When we take the court and represent Milwaukee and Wisconsin, we are expected to play at a high level, give maximum effort and hold each other accountable.

"We hold ourselves to that standard, and in this moment, we are demanding the same from our lawmakers and law enforcement.

"We are calling for justice for Jacob Blake and demand the officers be held accountable."

The NBA said in a statement on its Twitter account that the league and the National Basketball Players Association were announcing that “in light of the Milwaukee Bucks’ decision to not take the floor today for Game 5 against the Orlando Magic, today’s three games – MIL-ORL, HOU-OKC and LAL-POR have been postponed. Game 5 of each series will be rescheduled”.

The Bucks, whose star man Giannis Antetokounmpo was named defensive player of the year this week, are among the favourites to collect only the second NBA championship in their history.

In tennis, Naomi Osaka pulled out of a WTA match on Thursday.

She took to social media to explain she would no longer play her semi-final in the Western and Southern Open saying that "as a black woman I feel as though there are much more important matters at hand that need immediate attention, rather than watching me play tennis".

Baseball matches between the Cincinnati Reds and Milwaukee Brewers in Milwaukee, the Seattle Mariners and San Diego Padres in San Diego, and the Los Angeles Dodgers and San Francisco Giants in San Francisco were also postponed.

“The players from the Brewers and Reds have decided to not play tonight’s baseball game,” players from both teams said in a joint statement.

The impact on sports comes following three nights of unrest since the police shooting of a Jacob Blake.

Last night, a teen was arrested after two people were killed in a possible vigilante attack carried out by a young white man who was caught on mobile phone video opening fire in the middle of the street with a semi-automatic rifle during Black Lives Matter protests in Kenosha. 

Commander Norman Johnson, of the Antioch Police Department, Illinois, said the suspect - a young man whose name was not released because he is under 18 - was arrested on suspicion of first-degree intentional homicide.

Two people were killed in a possible vigilante attack carried out by a young white man who was caught on mobile phone video opening fire in the middle of the street with a semi-automatic rifle.

One victim was shot in the head and the other in the chest, the sheriff told the Milwaukee Journal Sentinel. A third person suffered gunshot wounds not believed to be life-threatening.

According to witness accounts and video footage, police apparently let the young man responsible for the shootings walk past them with a rifle over his shoulder as members of the crowd were yelling for him to be arrested because he had shot people.

Sheriff David Beth told the Journal Sentinel that armed people had been patrolling the city's streets in recent nights, but he did not know if the gunman was among them.

Mr Beth said: "They're a militia. They're like a vigilante group."

The FBI said it is assisting in the case.

Wisconsin Lieutenant Governor Mandela Barnes, who is black, said in an interview with the US news programme Democracy Now! that the shootings were not surprising and that white militias have been ignored for too long.

Mr Barnes said: "How many times across this country do you see armed gunmen, protesting, walking into state capitals, and everybody just thinks it's OK? People treat that like it's some kind of normal activity that people are walking around with assault rifles."

In one mobile phone video of the night's events, shots can be heard and the young man with a rifle is on the phone and appears to say "I just killed somebody" before he runs away. People are then shown tending to a white man who appears to have been shot in the head.

In another video posted online, the same young man with a rifle is jogging down the middle of a street as a crowd and some police officers follow him. Someone in the crowd can be heard asking "what did he do?" and another person responds that the man had shot someone.

The man with the gun stumbles and falls, and as he is approached by people in the crowd, he fires three or four shots from a seated position, hitting at least two people, including one who falls over and another who stumbles away to cries of "Medic! Medic!".

A witness, Julio Rosas, 24, said that when the gunman stumbled, "two people jumped onto him and there was a struggle for control of his rifle. At that point during the struggle, he just began to fire multiple rounds and that dispersed people near him".

"The rifle was being jerked around in all directions while it was being fired," Mr Rosas said.