Ibrahim Hassan al-Asiri, a reputed al-Qaeda bombmaker, is the key suspect in the parcel bomb plot [Reuters]

France's interior minister has said that one of the two parcel bombs intercepted last week after being sent from Yemen was defused 17 minutes before it was set to explode.

Brice Hortefeux made the claim during an interview with France-2 television on Thursday, but did not reveal his source for the information.

The two bombs were sent via air cargo to synagogues in the US but were intercepted in the UK and Dubai.

The synagogues' addresses were reportedly out of date, and David Cameron, the UK prime minister, has said the bomb discovered in Nottingham was set to explode in midair, leading to speculation that neither was intended to reach their destination in Chicago.

Both bombs were concealed within computer printers, where the ink cartridges were packed with the explosive material pentaerythritol tetranitrate, or PETN, and wired to cell phones with the SIM cards removed.

This would disable the phones' call-making ability, meaning that the plotters may have planned for the phones' alarms to set off the explosives.

Parcel inspections

A major military and intelligence operation is under way in Yemen as authorities attempt to track down an alleged Saudi bomb maker who is a key suspect in the foiled bomb plot.

The hunt for Ibrahim al-Asiri, 28, was launched in the provinces of Maarib and Shabwa, a security official told the Reuters news agency.

"Asiri is believed to be hiding and moving with senior al-Qaeda elements such as Nasser al-Wahayshi [the Yemen al-Qaeda leader]. Security intelligence are still tracking them down to exactly identify their whereabouts," the official said.

Al-Asiri is a reputed al-Qaeda bombmaker who last year hid an explosive in a "body cavity" of his younger brother, Abdullah, who then blew himself up in Jeddah in a failed attempt to kill a high-level Saudi counterterrorism official, Prince Mohammed bin Nayef.

The Yemeni government has responded to the parcel plot by announcing a plan to begin searching every piece of cargo sent from the international airport in Sana'a. In addition, workers will scan half of all cargo.

Many countries had already suspended passenger flights to and from Yemen; the bomb plot has led Yemenia, the national carrier, to stop carrying cargo to Europe.