The Defense Ministry carried out a test of its new rocket propulsion system on Tuesday morning.
The noise startled commuters in southern and central Israel, but the Ministry stressed that the rocket launch was simply a pre-planned test.
"The test was planned by the defense establishment long in advance, and was carried out as planned," it said.
Many residents in Petah Tikva, Lod, Ashdod, Sderot, Be'er Sheva, and Netivot reported a long cloud or smoke trail appearing in the sky, accompanied by an ear-splitting noise.
No further details were provided on the experiment, but several Israeli news sites say that the test was a ballistic missile test.