Five police officers dead in sniper attack in Dallas

The US city of Dallas has been rocked by an organised attack on police officers during a protest over the deaths of Philando Castile and Alton Sterling, in which so far five law enforcement officials have been killed.

Six more have been wounded in the Texan city attack which was carried out by a pair of snipers in the downtown area.

A suspect was being holed-up in a second floor garage in the city and police said that he was exchanging gunfire.

"The suspect we're negotiating with ... has told our negotiators that the end is coming and he's going to hurt and kill more of us, meaning law enforcement, and that there are bombs all over the place and downtown, so we're being very careful with our tactics, so we don't put our officers in harm's way, or the citizens," Brown said.

Three people are in custody and police released a photo of an additional man who was regarded as a suspect, before he handed himself in to officers before being released. He is said to be the brother of one of the protest organisers.

Footage circulating on Twitter has shown the reaction of citizens and police in the immediate aftermath of the first shots in Dallas.

Another video has shown the moment that a Dallas law enforcement officer confronted a shooter with a semi-autmoatic weapon, before being shot in the back by the man.

The attacks have come after the fatal shootings of two black men by police officers in Louisiana and Minnesota, Alton Sterling and Philando Castile. The demonstration in Dallas was organised a protest against the deaths.