Dallas shooting

The Dallas attack marks the deadliest day for US law enforcement officers since the 9/11 attacks in 2001.

Reacting to the latest shootings, presumptive Democratic presidential nominee Hillary Clinton said: "There is too much violence, too much hate, too much senseless killing, too many people dead who shouldn't be. No-one has all the answers. We have to find them together."

Meanwhile, her Republican opponent Donald Trump said in a video the shooting in Dallas "has shaken the soul of our nation".

He added: "The deaths of Alton Sterling in Louisiana and Philando Castille in Minnesota also make clear how much more work we have to do to make every American feel that their safety is protected."

Philando Castile was shot dead after being stopped in his car by police in St Paul, Minnesota , on Wednesday. Alton Sterling was killed by police a day earlier in Baton Rouge, Louisiana.

Both incidents were captured on video, reigniting what has become a national debate.

                                                                                                                      ''BBC News''