Police in Dubai said on Saturday that the bomb discovered there in a shipment of air cargo from Yemen that was bound for the United States contained the powerful explosive PETN and bore the hallmarks of al-Qaeda.

The white powder explosives were discovered in the ink cartridge of a computer printer, said a police statement carried by official state news agency.

The device was rigged to an electric circuit, and a mobile phone chip was hidden inside the printer, the statment said.

The bomb, sent from Yemen in a FedEx shipment, was prepared in a “professional manner,” police said.

PETN is the same chemical used in the failed attempt to blow up a U.S.-bound airliner on Christmas Day. That plot has been linked to al-Qaeda’s offshoot in Yemen.

“The plot style carries features similar to previous attacks carried out by terrorist organizations like al-Qaeda,” the Dubai police said.

“Swift action has enabled Dubai Police to foil a potential act of terror in the place the package was bound to,” the statement said.

The police said they were tipped off to the device by a call from abroad, but did not name the country.

The tip warned of the possibility of an explosive device hidden in postal packages onboard the FedEx flight originating from Yemen to Dubai, according to the statement.

Police said tests showed the printer cartridge also contained lead azide, an explosive compound that can be used in bomb detonators.