Iran has said Israeli involvement in Friday’s attack is still to be established and dismissed the drones used as like children’s toys.
Foreign minister Hossein Amir-Abdollahian claimed they took off from within Iran and only flew a few hundred metres before being shot down.
Israel hasn’t commented but is widely believed to be behind the strike targeting an airbase and nuclear site near Isfahan.
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The US told a G7 meeting that Israel had told it about the attack “at the last minute”.
Israel had been weighing up how to respond to Iran’s unprecedented drone and missile attack on Israel last weekend – with Western powers urging restraint.
“It has not been proved to us that there is a connection between these and Israel,” Mr Amir-Abdollahian told Sky’s US partner NBC News.
Iran said its air defences destroyed three drones and reported no damage or casualties.
The foreign minister said they were “more like toys that our children play with” than a serious threat, as he sought to play down the threat.
Authorities and media in Iran have described it as an attack by unknown “infiltrators”, dismissing the notion it was an Israeli offensive that bypassed its border defences.
Experts have said the modest, targeted strike appeared designed to avoid further escalation and it appears – for now – to have dampened fears of direct war.
‘If not, then we are done’
Mr Amir-Abdollahian said Iran was still investigating the attack and reiterated Israeli retaliation would mean an immediate and severe response – “but if not, then we are done. We are concluded”.
Meanwhile, the former head of Israel’s national security council said he didn’t believe there would be “real escalation” after Friday’s limited attack.
Major General Giora Eiland told Sky’s Yalda Hakim the strike showed Israel can reach “even sensitive places”, but it had tried to “do it in a way that both sides can be satisfied”.
He said both nations would try to emphasise their own success and minimise that of the other side.
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Military analyst Professor Michael Clarke said it made sense for Iran to try to downplay the attack.
He said it “relieves them of the responsibility of being so outraged they have to do something even more decisive”.
Prof Clarke added that Israel almost certainly used ballistic missiles, rather than drones, but that ultimately both sides were “trying to save face”.
Friday’s strike came after Iran launched an aerial assault on Israel on 13 April, involving about 300 drones and missiles.
It was mostly intercepted and no deaths were reported, but was a dramatic moment that bypassed the usual method of attacks via proxy groups.
Iran’s attack was itself retaliation for a strike – attributed to Israel – on an Iranian consulate in Syria on 1 April.
Two generals and seven members of Iran’s revolutionary guards were killed in the incident.
The Israel-Hamas war – which has seen attacks by Iranian and Israeli proxies increase – has helped create the conditions for this week’s historic flare-up.