Islamists claiming allegiance to Islamic State have issued a threat against Heathrow, LAX and JFK airports, warning that one of them would be targeted over the July 4th weekend.<br />The account said that attacks would be carried out on planes 'flying from Heathrow to the US' and warned that 'there will be a device placed in either Heathrow, LAX or JFK airports.'<br />The threat was revealed by SITE Intelligence Group - the world's leading non-governmental counterterrorism organization - on its website.
