Mark Barden, whose son Daniel was among those killed in the Newtown massacre, has said families of the victims are heartbroken at the Senate's blocking of gun ownership legislation but will continue to campaign for stronger weapon controls.
He issued an emotional plea at the White House after a plan aimed at expanding background checks for gun buyers failed to receive enough support in a vote.
With President Obama looking on, Mr Barden said: "We always knew this would be a long road. We don't have the luxury of turning back."
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Cloud and outbreaks of rain will ease away eastwards during the morning, clearing the east coast around midday with sunny spells developing.
Police and emergency services are attending the scene.
Rebel-held east remains at risk while the pumping station supplying the western part of the city is once again in operation.