Yemen on Monday announced crackdown on all cargo shipments after two US-bound bomb parcels were sent from the country, while an alleged Saudi bombmaker emerged as key suspect behind the package plot. State news agency Saba said Yemen's national committee for civil aviation security has decided "to implement exceptional security measures on all cargo leaving Yemeni airports to ensure the safety of civil aviation."The committee in a statement had also decided to tighten general security at all Yemeni airports, to counteract "methods used by terror organisations," Saba said. Qatar Airways said on Sunday that a package containing explosives was flown from Sanaa to Doha and then on to Dubai on one of its aircraft. A source said on condition of anonymity that the plane was a passenger flight. The bomb had PETN hidden inside a computer printer with a circuit board and mobile phone SIM card attached, officials said.The other parcel was found at East Midlands airport in central England and apparently travelled through Cologne in Germany. British Prime Minister David Cameron said it appeared designed to blow up a plane.Shortly after the discovery of the bombs, Britain banned all freight from Yemen from coming into the country, including in transit. On Saturday, Germany and France took similar measures to suspend air freight from Yemen. A US official in Washington, meanwhile, said Ibrahim Hassan al-Asiri, a 28-year-old alleged Al-Qaeda bombmaker, had emerged as a "leading suspect" in the parcel bomb plot uncovered late Thursday."Al-Asiri's past activities and explosives' experience make him a leading suspect," the official said on condition of anonymity.he militant, thought to be hiding in Yemen, is wanted for a string of high-profile attacks linked to Al-Qaeda in the Arabian Peninsula (AQAP), the Yemen-based branch of Osama bin Laden's network."There are indications he may have had a role in past AQAP plots, including the attempted assassination of a Saudi official and last year's failed Christmas Day attack," the official said. US counter-terrorism chief John Brennan also linked the attempted Christmas Day bombing and the package plot, both of which involved the high explosive PETN.Evidence suggested the same person built the intercepted parcel bombs and the device worn by the "underwear" bomber Umar Farouk Abdulmutallab who botched an attack on a flight to Detroit on Christmas Day 2009, he said."I think the indications are right now based on the forensics analysis that it's an individual who has been responsible for putting these devices together, the same," he told ABC News Sunday."He's a very dangerous individual -- clearly somebody who has a fair amount of training and experience."Asiri features on most-wanted terror lists in both Yemen and Saudi Arabia.