"We are monitoring this on a daily basis," foreign ministry spokesman Majed al-Ansari told a news conference.

"We have nothing to be concerned about right now, but obviously prolonged escalation will have unpredictable consequences."

Israel launched an unprecedented air campaign against Iran's nuclear infrastructure on Friday, triggering deadly missile exchanges between the arch foes, which are now in their fifth day.

"We have to emphasise, when we are talking about the waters of the Gulf, it's the main source of water for all of us here in the region," Ansari said.

"The international community has to make it very clear that any targeting of nuclear facilities, any targeting of fuel or energy facilities in this region, would have ramifications that are unknown to us in the Gulf."

Iran has a nuclear power plant at Bushehr on the Gulf coast, though its uranium enrichment facilities, which have been targeted by Israel, lie hundreds of kilometres (miles) inland.

The UN nuclear watchdog, the International Atomic Energy Agency, said on Friday it had been informed by Iran that the Bushehr plant had not been targeted.

On Saturday, Israel struck a major Iranian gas facility on the Gulf coast serving the South Pars gas field, which is shared with Qatar.

Ansari said Qatar's own facilities in the field were "secure" but condemned the Israeli strikes on Iran's energy infrastructure as "reckless".