There are strong indications a machete-style attack which left a soldier dead on a south east London street was a terrorist incident, an emergency meeting of politicians and police chiefs heard this evening.

The Cobra meeting, which was attended by the Defence Secretary Philip Hammond, Mayor of London Boris Johnson and Met Commissioner Sir Bernard Hogan-Howe heard that security has been tightened at Woolwich barracks and increased at all London barracks, Downing Street said.

The meeting had been called after a man was killed and two others were taken to hospital with gunshot wounds today following a “serious incident” understood to involve a serving soldier.

One of the attackers behind the barbaric killing, near the Royal Artillery Barracks in Woolwich, was filmed wielding a bloodied meat cleaver, saying: “We swear by almighty Allah we will never stop fighting you.”

Speaking from Paris, Prime Minister Mr Cameron said: “We will look at every aspect of security, we will look at every aspect of what you can learn from these incidents.

“But we also have to remember that in a free country like ours, the best way to defeat terrorism is to make sure that you continue to go about your life, to live your life and show that terrorists can never win, and that’s important.”

Earlier, several witnesses described seeing a “beheading” while another described seeing a man wearing a Help for Heroes T-shirt being attacked with a machete-style knife and dumped in a south east London street.

The incident occurred some 200 yards from the Royal Artillery Barracks, adjacent to Woolwich Common, the historical home of the Royal Artillery.

The barracks, also known as the Woolwich station, now houses a number of the King’s Troop Royal Horse Artillery and independent companies of the Grenadier and Coldstream Guards.

One witness reported two men, in their 20s, waving knives and a gun around after the attack, and even asking people nearby to take pictures of them “as if they wanted to be on TV or something”. Another said she had seen one of the attackers run towards police clutching two meat cleavers.

Woolwich and Greenwich MP Nick Raynsford said it was his understanding that one person, a serving soldier, was dead and his two alleged killers were taken to hospital.

London Ambulance Service confirmed a man was found dead at the scene, while two other men were taken to hospital, one of them in a serious condition.

A spokesman for Ed Miliband said the Labour leader was cutting short a visit to Germany to return to the UK as soon as possible.