Moscow is seriously concerned by the latest developments in Syria and calls on sides to exercise restraint and avoid an escalation of the situation, the Russian Foreign Ministry said on Saturday.

Israel launched heavy air strikes in Syria on Saturday, saying it hit air defences and Iranian targets, and the Syrian army claimed to have brought down an Israeli F-16 that crashed in northern Israel in a major escalation of tension.

"We urge all sides to exercise restraint and to avoid any actions that could lead to an even greater complication of the situation," the ministry said in a statement.

"It is necessary to unconditionally respect the sovereignty and territorial integrity of Syria and other countries in the region."