According to a message post, the formerly unidentified Abu Dujanah al-Khorasani Brigade has accepted that it was responsible for sending out a tear gas letter to the embassy, last week. It was reported that the two workers of the embassy, who held the letter, underwent a check-up and were then discharged by the city hospital.

The French officials are examining the July 30 episode, Paul Patin said on Wednesday. It was deemed that the letter had traces of tear gas. But a senior U. S. executive, who wants to remain anonymous, said that according to the latest reports that have arrived at Washington, the alleged letter did not have tear gas or any other toxin.

A private expert, Evan Kohlman, who keeps an eye on terrorist websites said, "These letters, did not achieve their desired objective, due to the difficulty and complexity and the multitude of the substances involved".

The chemical letters are said to the most recent tool in a string of supposed messages from the followers of Al Qaeda.

A counterterrorism officer said that in places such as the tribal regions of Pakistan and Yemen, Al Qaeda and its supporters are said to be under a lot of stress.