Earlier, the United States and Russia reached an agreement on a ceasefire between the Syrian government and opposition groups to help end the country’s civil war.
"Over the past three days, the Russian Defense Ministry has relocated three additional modern unmanned aerial vehicle complexes to the Hmeymim airbase, two radars to detect small targets, allowing to record the use of artillery systems by terrorists," the ministry said in a statement.
The ministry added that control over the Syrian airspace is carried out by the air defense systems and Russian combat aircraft.
In late February, a coordination center for reconciliation of opposing sides in the Syrian conflict began operations at the Russian Hmeymim airbase in the Latakia province.
The Syrian government has confirmed its readiness to halt its military actions in accordance with the Russia-US agreement. Some opposition forces have been skeptical about the ceasefire, but in general have agreed to adhere to it. The ceasefire took effect on Saturday.