U.S. President Donald Trump delivered a sharp rebuke to both Israel and Iran as the ceasefire he helped broker appeared to unravel within hours of taking effect.

Trump urged Israel “do not drop those bombs,” following reports that the Israeli military had ordered “powerful strikes” in response to alleged Iranian aggression. Trump also used an expletive to criticize both nations for breaking the ceasefire terms, moments before asserting again that “the ceasefire is in effect.”

The confusion followed a turbulent night of cross-border hostilities. Israel claims it intercepted a missile launched by Iran just hours after the truce began. In response, Israel reportedly carried out one of its heaviest aerial bombardments in recent weeks, targeting sites in northern Iran.

Residents in Tehran witnessed massive explosions overnight. Iranian local officials say at least nine people were killed, including civilians. Meanwhile, in Israel, emergency services in Beersheba confirmed that four people were killed when a building being used as a shelter was struck.

Iranian authorities have denied launching new attacks, instead accusing Israel of escalating the situation. A senior Iranian military spokesperson warned that “any further aggression will be met with a decisive, firm, and timely response.”

With casualties mounting on both sides and diplomatic channels fraying, the viability of the Trump-brokered ceasefire is now in serious doubt.

Global leaders have called for an immediate return to restraint, though there is little sign either side is backing down.