The US Central Command said on X, formerly known as Twitter, that its F-15 fighter jets arrived in the Middle East.
"The 494th Expeditionary Fighter Squadron F-15E Strike Eagle aircraft arrived in the US Central Command area of responsibility to bolster the US posture and enhance air operations throughout the Middle East," it said in its statement.
Earlier, US Defense Secretary Lloyd Austin said "we've augmented U.S. fighter aircraft squadrons in the Middle East", stressing that "the US Department of Defense stands fully ready to deploy additional assets, if necessary."
The Palestinian movement Hamas launched its biggest assault on Israel in years, firing a barrage of rockets from Gaza and sending fighters across the border.
Israel said it was on a war footing and began its own strikes against Hamas targets in Gaza, with Israeli media reporting gunbattles between bands of Palestinian fighters and security forces in southern Israel.
For his part, Israeli Prime Minister Benjamin Netanyahu vowed to destroy Hamas in a televised address on Friday, warning that the fierce bombardment of Gaza was "only the beginning" of his country's response to the attacks by Hamas last week.
His threat came as thousands of Palestinians fled to southern Gaza in search of refuge after Israel warned them to evacuate ahead of a possible ground offensive in Gaza, where the death toll from Israeli air strikes has surged to at least 1,900, according to the local health ministry.
