Bin Laden was worried that his wife had a tracking chip implanted in her tooth.

The al-Qaeda terrorist group's leader feared being tracked by drones and other secret devices, according to documents declassified yesterday.

Original bin Laden document and English translation. Photo: Reuters

According to NBC News, the US government yesterday announced 113 documents and letters confiscated on May 2, 2011, during the raid on the hideout of terrorist Osama bin Laden in Pakistan. Documentsmainly in the period 2009 - 2011,translated and declassified by US intelligence agencies.

In one letter, bin Laden was concerned about his wife's visits to the dentist while in Iran. He worried that a tracking chip might be implanted in a dental filling. "The chip is as long as a grain of wheat and as wide as a noodle," he wrote. The letter concluded with the instruction: "Destroy this letter after reading it."

In another document, bin Laden instructed all al-Qaeda members holding Afghan hostages to be wary of tracking technology that could be attached to ransom notes. "It is important to dispose of suitcases containing money, due to the possibility that they may be embedded with chips," bin Laden wrote to an aide identified only as S.haykh Mahmud.

Referring to armed US drones patrolling the skies, the terrorist leader advised his negotiators not to leave their rented house in the Pakistani city of Peshawar unless "the sky is cloudy".

US President Barack Obama said drone strikes and other counterterrorism operations had degraded al-Qaeda's leadership, culminating in the killing of bin Laden by US Navy SEALs on May 2, 2011. In the years since, the terrorist organization has operated from Afghanistan to North Africa, and the self-proclaimed Islamic State, which is ideologically opposed to al-Qaeda, has grown and expanded its territory.

According to VNE