Russia sent a volley of missiles at the eastern city of Dnipro on Thursday, Ukrainian officials said, the latest assault in a week of rising hostilities between the two adversaries.

Ukraine claimed Russia had used an intercontinental ballistic missile, which would have represented a significant escalation in its assaults. But several Western officials said that the weapon was not an ICBM and instead was likely an intermediate-range missile that flies shorter distances.

The officials spoke on condition of anonymity to discuss a private Western intelligence assessment.

The Ukrainians did not provide much detail on the strike, saying only that the missile had been launched from the Russian region of Astrakhan and was part of a volley aimed at Dnipro. The Russian Defense Ministry did not immediately respond to a request for comment.

President Volodymyr Zelensky said Russia had attacked Ukraine with a new class of missile. “All the parameters — speed, altitude — match those of an intercontinental ballistic missile,” he said. “All expert evaluations are underway.”

In the last few days, the Ukrainian military has used longer-range American and British missiles to strike deeper into Russia, after the two countries granted permission to do so. In response, President Vladimir V. Putin lowered the threshold for Russia’s use of nuclear weapons.

A former senior Ukrainian security official said it seemed likely that the Russian missile strike was intended to stoke fears of a widening war with Ukraine and its Western allies. “In fact, this is just a ballistic missile, just a big one,” the official said.