Plane bomb found only 17 minutes before it was due to detonate

Brice Hortefeux provided no other details in an interview on France's state-run France-2 television, or say where he got the information from.

When investigators pulled the Chicago-bound packages off cargo planes at East Midlands Airport and at Dubai on Friday, they found the bombs were wired to mobile phones and hidden in the toner cartridges of computer printers.

The SIM cards had been removed and the phones could not receive calls, officials said, making it likely the terrorists intended to use the alarm or timer functions to detonate the bombs.

They also said that each bomb was attached to a syringe containing lead azide, a chemical initiator that would have detonated PETN explosives packed into each printer cartridge.

Both PETN and a syringe were used in the failed bombing last Christmas of a Detroit-bound airliner.

Investigations have centred on the Yemeni al-Qaida faction's top bomb maker, who had previously designed the bomb that failed to go off on a crowded US-bound passenger jetliner last Christmas.

This time authorities believe that master bomb maker Ibrahim al-Asiri packed four times as much explosives into the bombs.

The two bombs contained 300 and 400 grams of the industrial explosive PETN, according to a German security official.

By comparison, the bomb stuffed into a terrorist suspect's underwear on the Detroit-bound plane last Christmas contained about 80 grams.

One of the explosive devices found inside a shipped printer cartridge in Dubai had flown on two airlines before it was seized, first on a Qatar Airways Airbus A320 jet to Doha and then on an as-yet-undisclosed flight from Doha to Dubai.

The number of passengers on the flights were unknown, but the first flight had a 144-seat capacity and the second would have moved on one of a variety of planes with seating capacities ranging from 144 to 335.

It also emerged last night that two brothers have been arrested in Paris, accused of planning a terrorist attack in France.

The French interior minister Brice Hortefeux said that the two French citizens were suspected of "criminal association with a terrorist enterprise" and were being questioned.

No other details have been released. He spoke amid heightened fears around Europe about terrorism threats.