HM the King said he had learnt of the sad news of the massive explosion with deep sadness and emotion.

     He expressed to President Obama and through him to the victims' families and the US friendly people his "hearteflt condolences and sincere compassion," wishing the injured swift recovery.

     The massive explosion is reported to have left scores of casualties and turned homes to rubble, with police saying the number of dead could be between five and 15.

     More than 160 people were injured and three to four firefighters were missing, according to officials.