The source added that the army forces also found over 100,000 rounds of machine-guns bullets, a large number of RPG rockets and a number of assault rifles.
Meantime, the Syrian army continued its military advances in other parts of Syria over the past 24 hours.
Tens of terrorists were killed and dozens more were injured during the Syrian army's operations in provinces across Syria.
Dara'a
The Syrian army discovered a large cache of arms and ammunition, which also included several US-made missiles, during cleansing operations against the remnants of the terrorist groups in Dara'a province in Southern Syria.
A Syrian military source reported on Saturday that the army's engineering units have found American TOW missiles in the weapons cache which belonged to the terrorists before being forced to leave Dara'a province.
The source added that the army forces also found over 100,000 rounds of machine-guns bullets, a large number of RPG rockets and a number of assault rifles.
Media reports revealed last month that the US was providing direct military support for the ISIL in trade for Syria's artifacts.
Hama
The Turkish Army forwarded a new military convoy to Northern Hama on Saturday amid the Syrian Army's preparation for a large-scale operation against Tahrir al-Sham Hay'at (the Levant Liberation Board or the Al-Nusra Front) and its terrorist allies in the Northern and Northwestern parts of the country.
The Turkish army sent a long military convoy, accompanied by 5 military vehicles of the terrorists of the National Liberation Front, to Syria.
The convoy included 12 military vehicles, including personnel carrier vehicles and also logistical equipment.
The convoy was dispatched to 2 Ankara-run observation posts in the town of Morek and in the village of Shirmaqar in Northern and Northwestern Hama.
The Turkish convoy arrived in Hama as the Syrian army is readying to conduct a large-scale operation in the Northern and Northwestern parts of the country after Ankara failed to expel the terrorists from the demilitarized zone mentioned in Sochi Agreement.
The Syrian Army has dispatched a large number of forces and a large volume of military hardware to contact lines with the terrorists in Idlib, Hama and Lattakia provinces.
Hasaka
A bomb went off at a base of the Kurdish militia in a region at Northern Hasaka's border with Turkey and killed a sum of 13 gunmen, including a notorious commander, field sources reported on Saturday.
The sources said that a bomb exploded at the main base of the Syrian Democratic Forces (SDF) near the town of Ra'as al-Ein in Northwestern Hasaka and killed 13 militias, including Sardar Kobani, a notorious SDF commander.
A number of gunmen were also wounded, the sources said, adding that the Kurdish militia have put fighters on alert following the blast, and embarked on arresting tens of civilians.
Aleppo
The Syrian Democratic Forces (SDF) launched an offensive on the Ankara-baked militants in Northern Aleppo, and killed a number of them, including a commander of the Turkey-led Euphrates Shield Force on Saturday.
The SDF staged an assault on the Ankara-backed militants' positions West of the town of Azaz in Northern Aleppo.
In the meantime, other SDF units engaged in fierce clashes with the Ankara-backed al-Shamiyah Front in the village of Ablah near the town of al-Bab in Northeastern Aleppo on Friday, killing a number of militants, including Momtaz al-Dayeri, a commander. The SDF further seized a large volume of arms and ammunition in the attack.
The Ankara-led Euphrates Shield Force sent a large military convoy to the villages of Ablah and al-Hamran following the attack.
Meanwhile, the SDF launched artillery and missile attack on the Ankara forces' positions in Azaz and in the small town of Kaljabrin in Northern Aleppo, sources said, adding that the SDF tried to advance in Mar'anaz and al-Qazi regions in Northern Aleppo.
Lattakia
The Syrian Army troops are on high alert to kick off an imminent large-scale operation in the Northern and Northwestern parts of the country amid growing provocative measures by Tahrir al-Sham Hay'at and its allied terrorists in the demilitarized zone, a military source said on Saturday.
The source said that the army dispatched the 4th Division, who are elite forces of the army, to contact lines with the terrorists in Northern Lattakia, preparing for an imminent huge operation in the region.
According to Fars News Agancy, Tahrir al-Sham and its allies have also been fortifying their positions in the demilitarized zone, intensifying attacks on government forces' strongholds.
The source said that the army may launch operation from Kbabana strategic heights in Northern Lattakia.
The army has been pounding the positions of Tahrir al-Sham and its allied in Northern Hama, Southern Idlib, Western Aleppo and Northwestern Lattakia in recent days to weaken their combat capabilities.
The terrorists' refusal to implement the Sochi Agreement to establish a demilitarized zone is pushing the army to initiate its long-waited assault on militants in Idlib that had been put on hold due to the Sochi Agreement.
847/940