A Syrian military source said that the Syrian military has started using new types of air and ground weapons supplied by Russia.

The Syrian military has recently started using new types of air and ground weapons supplied by Russia, a Syrian military source said on Thursday.

The source described the weapons as highly accurate and effective, adding that the army had started using them in recent weeks having been trained in their use in Syria in recent months.

“New weapons are being delivered, and new types of weapons. The Syrian army is being trained in the use of these weapons. In fact, the army has started using some of these (weapon) types,” the source said in response to a question about Russian military support.

“The weapons are highly effective and very accurate, and hit targets precisely,” the source told Reuters. “We can say they are all types of weapons – be it air or ground.”

The source declined to give further details about the weapons.

Facing a manpower problem in the army, the Syrian government has lost ground this year in the northwest, the southwest and the center of the country to an array of groups including ISIS and other insurgents battling to topple President Bashar al-Assad.

U.S. officials said on Wednesday the they had identified a small number of Russian helicopters at a Syrian airfield, the latest addition to what Washington believes is a significant Russian military buildup in the country.

One of the officials said four helicopters had been identified, including helicopter gunships, although it was not clear when the Russian helicopters had arrived there.

Reuters has previously reported on U.S. assessments that Russia has sent about 200 naval infantry forces, battle tanks, artillery and other equipment to an airfield near Latakia.

Thus far in the conflict, Iran and its Lebanese ally Hezbollah have been the main source of military support for Damascus. Hezbollah has deployed directly in combat, while Iran has mobilized militias and sent military advisers.

Lebanese sources familiar with military and political developments in Syria have also previously told Reuters that Russians are taking part in military operations in the country.

Syrian officials say the Russian military presence is restricted to experts.