The Free Syrian Army spy boss said he had been sending reports to his CIA contacts for more than two years that included GPS coordinates, Daesh movements, photographs and phone numbers.
His operation - which utilizes 30 operatives placed inside Daesh-controlled cities - was 'trained abroad' and received $10,000 per month from the US government, he claimed.
The spy chief, interviewed by Le Monde and named only as 'M', said: "From the moment [Daesh] had 20 members to when it had 20,000, we have shown everything to the Americans."
"When we asked them what they did with this information, they always gave evasive answers, saying it was in the hands of decision-makers," the Daily Mail reported.
"My agents also managed to get hold of phone numbers of Daesh officials, serial numbers of satellite equipment and IP addresses. But once again, zero response."
Among the intelligence details cited were a photograph and GPS coordinates of a secret Daesh training camp in Latakia Province, Syria.
Another document was 2014 a battle plan designed to expel Daesh from Aleppo. However, it revealed the attack was postponed several times by the US before a counter attack from Al Qaeda's Al-Nusra Front scuppered it.Today, control of Aleppo is torn between government and opposition factions and is the scene of some of the worst civilian casualties of the entire Syrian war.
Years of bombing has also fuelled the migrant crisis currently seen gripping Europe as thousands flee their homes in the city.