The Sunday report by the Lebanese daily Al Akhbar said Qatari officers Saeid al Hajeri and Faleh bin khalid al Tamimi sneaked chemical materials through the Turkish border into Syria, where they were used by militants to launch a deadly attack on Aleppo’s Khan al-Asal district.

The report adds that details of the case have been handed over to the Russian intelligence agency.    

Damascus called for an international probe into the attack that killed over two dozen Syrians.

This came as some Western states accused the Syrian government of using chemical weapons against foreign-backed militants operating in the country.

French officials claimed on June 4 that they were in possession of “evidence,” based on laboratory tests that proved nerve gas Sarin had been used by the government forces in Syria.

Damascus strongly rejected the claim as “lies,” saying that the militants have used chemical weapons on several occasions, including the attack in the region of Khan al-Asal.

The foreign-sponsored militancy that has gripped Syria for more than two years has so far resulted in the killings of many people, including large numbers of Syrian soldiers and security personnel.