Around 150 protesters gathered outside the plush property in Belgrave Square one of central London's finest squares, which houses a string of embassies. A Scotland Yard spokesman said the arrests were for public order offences after the demonstration broke out at around 2:00am (0200 GMT). The spokesman said "appropriate policing" was now in place.The demonstration occurred amid reports that Syrian forces killed at least 217 civilians, including women and children, in a "massacre" in the central city of Homs, ahead of a United Nations vote on the repression. "Officers are at the scene and appropriate policing is in place," the Scotland Yard spokesman said. "Five males gained entry to the building. They have now been arrested."The BBC said embassy windows had reportedly been smashed and demonstrators reported being prevented from leaving by the police.