Syrian TV are reporting that an explosion in Damascus has hit the main gate of the Syrian Interior Ministry.
A resident has said she heard sirens and shooting after a "huge explosion".
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A second police officer has died after he and a colleague were shot as they scuffled with a suspect in Florida.
Thousands of demonstrators have marched through Boston in opposition to a right-wing rally in the city which was eventually cut short.
Some 1,000 counter-protesters blocked 500 neo-Nazi demonstrators as they tried to march to the site of the death of Hitler ally Rudolf Hess.