The secretary general of the Arab League has said its approval of unprecedented sanctions has sent a very serious political message to Syria. Nabil al-Arabi told the BBC that the Syrian government could not carry on as if it was business as usual. He said new sanctions recently agreed by Arab states would come into force on Saturday unless Syria kept its promises.Syria's foreign minister has described the sanctions as "economic war". In a BBC interview at the Arab League headquarters in Cairo, Mr Arabi said the Arab League had agreed to sanctions "with a heavy heart".