A man killed in a suspected terrorist attack in south-east London was a member of the armed forces, senior Whitehall sources have confirmed for BBC.
The PM is to chair a Cobra emergency response committee later.
David Cameron flew back from France yesterday to lead the government response. The meeting will be attended by politicians, the UK's most senior police officer and the new head of MI5.
Meanwhile, security has been increased at barracks across London.
The two suspects were shot and wounded by police after the attack - which took place in John Wilson Street, the A205, at 14:20 BST.
One is in a serious condition while the other is also being treated for injuries.
The two men spent the night under arrest in hospital as counter-terrorism police investigate the killing in Woolwich.
One man - his hands covered in blood- was filmed by a passer-by, saying he carried out the attack because British soldiers killed Muslims every day.