This article is more than 9 years old

This article is more than 9 years old

American officials have warned airlines that they believe al-Qaida is developing "belly bombs" to beat airport security and allow suicide bombers to launch terror attacks on board passenger planes.

The department of homeland security has sent a bulletin to airline executives saying it has identified a potential threat from terrorists who could "surgically implant explosives or explosive components in humans".

Although many airports use advanced imaging technology that can "see" through people's clothing, the technology might not pick up a bomb which is hidden inside a body.

"Due to the significant advances in global aviation security in recent years, terrorist groups have repeatedly and publicly indicated interest in pursuing ways to further conceal explosives," said Kawika Riley, spokesman for the department's transport security administration.

"As a precaution, passengers flying from international locations to US destinations may notice additional security measures."

Experts say the explosives could be implanted in abdomens, buttocks and breasts allowing suicide bombers to pass undetected through airport body scanners. Explosive compounds such as pentaerythritol tetranitrate (PETN) could be implanted, then the person's wounds allowed to heal, making the material difficult to detect. On board the plane, the material could be detonated by injection.

US officials have been on high alert for terror attacks since US forces killed al-Qaida's leader, Osama bin Laden in May. They say there is no intelligence about a plot, but US and international carriers are being urged to consider the threat.

The bombs are thought to be a particular risk in Europe and the Middle East where full body scanners are not as widely used as they are in the US.

Authorities told ABC News that these "belly bombs" were thought to be the work of 28-year-old Ibrahim Asiri, who became a high-profile target for the US after his failed attempt to hide bombs in printer cartridges being moved from Yemen to Chicago.

He was also believed to be behind the attempted bombing of Northwest Airlines Flight 253 on 25 December 2009 by the "underwear bomber", Umar Farouk Abdulmutallab.

The Nigerian had a pouch of PETN in his underwear. He tried injecting the pouch with a chemical to create a detonation but he set his clothes on fire instead and was overpowered by passengers.

Research conducted by the BBC after the underwear bombing suggests that Abdulmutallab would have failed to damage the plane's fuselage even if the bomb had gone off.

The BBC documentary claimed that the blast would only have been strong enough to kill the bomber and the person who was sitting next to him.

Al-Qaida terrorists are believed to have hidden explosives inside their bodies for suicide bombings. In August 2009 Asiri's brother, Abdullah Hassan, died trying to kill Saudi Arabia's deputy interior minister with a bomb reported to have been hidden in his rectum. Saudi officials subsequently told CNN that the bomb may have been hidden in his underwear.

• This article was amended on 7 July 2011. The original said that Al-Qaida terrorists are known to have hidden explosives inside their bodies for suicide bombings. This has been corrected and the text updated.