The US State Department said on Saturday that it has "credible reports" that Hamas could violate the ceasefire with an attack on Palestinian civilians in Gaza.
If the attack takes place, it "would constitute a direct and grave violation" of the agreement forged by President Donald Trump to end the two-year war between Israel and Hamas, the statement said.
No further details were disclosed about the potential attack.
"Should Hamas proceed with this attack, measures will be taken to protect the people of Gaza and preserve the integrity of the ceasefire," the State Department said.
Emphasising on its commitment to protect Palestinians and maintain stability in the region, the State Department reiterated that any aggression from Hamas will violate the terms for the ceasefire, while also threatening diplomatic efforts towards peace.
“The United States and the other guarantors remain resolute in our commitment to ensuring the safety of civilians, maintaining calm on the ground, and advancing peace and prosperity for the people of Gaza and the region as a whole,” the statement added.
Trump previously warned on social media that "if Hamas continues to kill people in Gaza, which was not the Deal, we will have no choice but to go in and kill them."
The US president later clarified he won't send US troops into Gaza after launching the threat against Hamas.
"It's not going to be us," he told reporters. "We won't have to. There are people very close, very nearby that will go in and they'll do the trick very easily, but under our auspices."
Trump's hostile rhetoric represented a shift after initially expressing nonchalance about Hamas killings, saying they had taken out "a couple of gangs that were very bad."
The Israeli military launched a campaign in Gaza in response to the 7 October 2023 attack, in which Hamas-led gunmen killed about 1,200 people in southern Israel and took 251 others hostage.
At least 68,000 people have been killed by Israeli attacks in Gaza since then, according to the Hamas-run health ministry, whose figures are seen by the UN as reliable.
In September, a UN commission of inquiry said Israel had committed genocide against Palestinians in Gaza. Israel categorically rejected the report as "distorted and false".