GERMAN intelligence believes the Syrian regime was behind last month's chemical attack, but the largest death toll may be the result of a dosage "mistake", news site Spiegel Online reported.
Spiegel cited secret briefings to lawmakers reportedly given by Mr Gerhard Schindler, director of Germany's BND foreign intelligence service.
The BND chief said that only President Bashar al-Assad's military and not the rebels had substances such as sarin gas and the capability to fire them using 107-mm calibre missiles, of which it has a significant stockpile.
But Mr Schindler said the heavy number of casualties, which the US has estimated at more than 1,400 people, pointed to a possible mistake in the dosage.
In his classified briefings, he reportedly said that in other attacks in Syria earlier this year where chemical weapons were allegedly used, "the poison gas mixture was strongly diluted, explaining why they caused far fewer deaths", Spiegel Online said.
The BND chief said it was possible the regime had ordered the use of poison gas as way of intimidating the rebels on the outskirts of the capital Damascus.
The Spiegel report said Mr Schindler considered it "possible that a mistake was made in mixing the gas and that much more poison than planned was fired".
During one 30-minute presentation, he also mentioned that BND had intercepted a telephone conversation between a high-ranking official of the Lebanese Shiite movement Hezbollah, a traditional ally of the Syrian regime, and an Iranian diplomat.
The Hezbollah official had attributed last month's attack to Mr Assad and said he felt the leader had "lost his nerve" and committed a "serious mistake" in giving the order to use chemical weapons, said Spiegel. - AFP.