U.S. Secretary of State Tony Blinken alerted his G7 counterparts on Sunday about a potential imminent attack by Iran and Hezbollah against Israel, which could begin as early as Monday, according to sources briefed on the call.

Blinken organized the conference call to coordinate with close U.S. allies and to exert last-minute diplomatic pressure on Iran and Hezbollah to mitigate their retaliation.

He emphasized that minimizing the impact of their strikes is crucial to preventing a full-scale war.

Iran and Hezbollah have vowed to respond to the assassinations by Israel of Hamas political leader Ismail Haniyeh in Tehran and Hezbollah military commander Fuad Shukr in Beirut.

Blinken stressed that the U.S. believes both Iran and Hezbollah will retaliate, although it is unclear what form the retaliation will take.

He also noted that the U.S. does not know the precise timing of the attacks but warned that they could start within the next 24 to 48 hours, meaning as early as Monday. He stated that the U.S. is making efforts to break the cycle of escalation by trying to limit the attacks by Iran and Hezbollah as much as possible and then restrain the Israeli response.

Blinken urged the other foreign ministers to apply diplomatic pressure on Iran, Hezbollah, and Israel to exercise maximum restraint.

Blinken also mentioned that the recent boost in U.S. forces in the region was purely for defensive purposes.

One source described Blinken as sounding frustrated when he briefed the ministers on recent talks with Israel over a Gaza hostage and ceasefire deal. Blinken expressed that the administration had felt close to a breakthrough before the assassinations in Tehran and emphasized that a deal is now needed more than ever.

In a statement, the G7 ministers expressed deep concern over the heightened level of tension in the Middle East, warning that it threatens to ignite a broader conflict in the region. They urged all involved parties to refrain from perpetuating the current destructive cycle of retaliatory violence, to lower tensions, and to engage constructively toward de-escalation, stating that no country or nation stands to gain from further escalation in the Middle East.