Obama: our time here is precious

President Barack Obama called off his campaign schedule for the day to return to the White House in reaction to the shootings. In a speech, he said: "We may never understand what leads anybody to terrorise their fellow human beings like this."

He added: "This is reminder that life is very fragile. Our time here is limited and precious.There will be other days for politics. This is a day for prayer and reflection."

In addition, the planned premiere of The Dark Knight Rises in Paris, France this evening was cancelled by film company Warner Brothers out of respect for the tragedy.