The US Homeland Security has warned airports all over the world against suspicious stuffed items among luggage after US intelligence concluded that Al-Qaeda operatives are being trained to conceal 'nitrocellulose' bombs inside them, reports said on Tuesday. Intelligence officials have confiscated Al-Qaeda manuals and picked up several indications that the network is attempting to create a chemical called nitrocellulose to fashion explosive devices that could be smuggled aboard jetliners, The Washington Post quoted Homeland officials as saying. "We judge this type of threat to be real and continuing. We have received reports from several credible, independent sources that Al-Qaeda is...