Israel's Prime Minister Benjamin Netanyahu was likely told of the US drone strike on General Qassem Soleimani before the attack.
US Secretary of State Mike Pompeo is understood to have briefed Israel ahead of time about their plans to kill the revered military leader who was the powerful head of Iran's elite Quds Force.
Pompeo spoke to Netanyahu on the phone on Wednesday night, ostensibly to thank him for Israel's help after the attack on the US embassy in Iraq, according to The Times of Israel.
But on Thursday morning, hours before the attack in Baghdad, Netanyahu forewarned about 'very, very dramatic things' happening in the region.
He tweeted: 'I want to make one thing clear: We fully support all of the steps that the US has taken as well as its full right to defend itself and its citizens.
'Moreover, we know that our region is stormy; very, very dramatic things are happening in it. We are alert and are monitoring the situation.
'We are in continuous contact with our great friend the US, including my conversation yesterday afternoon.'
Just hours later, Soleimani and other top officials were killed in the airstrike which could have far-reaching and catastrophic consequences.
But it appears the US did not brief allies other than Israel of the impending attack, with Britain not given any notice ahead of the airstrike.
In a statement after Pompeo's call with Netanyahu, the US State Department said: 'Secretary Pompeo thanked Prime Minister Netanyahu for Israel's unwavering commitment to countering Iran's malign regional influence and its condemnation of the December 31 attack on the US Embassy in Baghdad.
'The Secretary and Prime Minister reaffirmed the unbreakable bonds between the United States and Israel.'
After the strike, Netanyahu praised the US and Donald Trump and gave his full support behind the killing, saying the President acted with 'determination, strongly and swiftly'.
Pompeo has since briefed other foreign ministers in Britain, Germany and China, stressing that Trump was countering a real and imminent threat to US lives in the region.
He also said the President is committed to deescalating tensions despite the initial outcry after the attack.
This article has been adapted from its original source.