Video seems to capture the moment shots were fired in London Bridge

Three attackers were being hunted down by the 70-strong Special Forces unit which was dispatched on the direct orders of the Home Secretary.
The 'Blue Thunder' squad - an elite Special Forces unit which can be scrambled at a moment's notice - was dispatched to join in the hunt for the attackers.
It had been rehearsing terror scenarios for months - including how to take out lone wolves and multiple rampaging jihadis.
It comes just days after Theresa May reduced the country's terror threat level down from critical to severe, which means that a terrorist attack is 'highly likely'.
Thousands of armed police officers were deployed across the streets of Britain after the Manchester Arena attack, in which 22 people were killed.
Speaking outside Scotland Yard this morning, Metropolitan Police Commissioner Cerrisa Dick has now confirmed that a seventh person was killed in last night's attack at London Bridge and Borough Market.
She said: 'As you know, our officers confronted suspects and brought this terrible incident to a conclusion within eight minutes.
'This is a fast-moving investigation. We will have increased patrols in many areas by police and this will include armed police.'
London Bridge station and underground station remain closed as armed police carry out a search of Borough Market.
Soldiers in the Blue Thunder unit - which is nicknamed after its unmarked helicopter - were supported by an Apache helicopter gunship which uses powerful cameras to relay live pictures to commanders on the ground.