Syrian Deputy Foreign Minister Faisal Mekdad has called Israel's attack on a military research facility a "declaration of war".

In an interview with CNN, he says the attack represents an alliance between terrorists and Israel, that Syria would retaliate in its own time and way.

Israel is yet to confirm the strike, but sources say it targeted weapons bound for Hezbollah militants in Lebanon. 

It is the second suspected Israeli strike in two days.