FILE PHOTO: People watch S-300 air defense missile systems launching missiles during the Keys to the Sky competition at the International Army Games 2017 at the Ashuluk shooting range outside Astrakhan, Russia, August 5, 2017. REUTERS/Maxim Shemetov/File Photo

Beirut - Washington - London - Asharq Al-Awsat

The Russian army began moving components of its S-300 defense system from west Syria to Deir Ezzor, where the US-led coalition forces are positioned, diplomatic sources said Monday.

Russian President Vladimir Putin decided to deliver the sophisticated S-300 defense system to Syria last September following the downing of a Russian spy aircraft during an Israeli airstrike.

Moscow had previously deployed S-400 and normal S-300 missile defense systems in Syria.

“In the past days, Russia began moving some parts of the S-300 sophisticated system to Deir Ezzor, a step that would make the flyover of coalition planes (in missions) against ISIS east of the Euphrates River more difficult,” the sources said.

In May last year, Moscow and Washington signed a memorandum of understanding to regulate the flyover of all aircraft and drones in Syria and prevent a clash between the two sides.

Monday’s reports on the S-300 defense system came amid confusion by the Syrian regime media concerning reports that Israeli warplanes had launched an attack on Damascus international airport.

The official Syrian government mouthpiece SANA reported that the country’s air defenses had been triggered by incoming “hostile” missiles.

Experts said that Sunday’s operation might have been triggered by Israel to test the new S-300 defense system.

Meanwhile, the Syrian Democratic Forces (SDF) succeeded Monday to recuperate the Hajin hospital, one of the most important ISIS-held areas east of the Euphrates, following battles with militants near the Iraqi border.

“Our forces succeeded to recuperate the hospital building, which was largely destroyed following battles with ISIS militants,” a commander from the Deir Ezzor Military Council told the German news agency.

He added that battles were very fierce, but would continue until the SDF forces recapture the whole city.

The Syrian Observatory for Human Rights said the SDF has amassed 17,000 fighters of allied militias from Kurdish-controlled areas in northern and eastern Syria to take part in the battle against ISIS.