US loses patience with ceasefire in Syria

The United States says its lost patience with the ceasefire in Syria and warns it will take action if the situation does not improve.

There has been an upsurge in violence in recent days after a huge explosion in Hama on Wednesday.

The UN Secretary General, Ban ki Moon, has said he is gravely alarmed at the continued killing in Syria and is urging the Assad regime to withdraw heavy weapons from populated areas.

The BBC's Wendy Urquhart reports.