The concerns were made during a phone call between Israeli prime minister Yair Lapid and Ukrainian Foreign Minister Dmytro Kuleba on Thursday.
The meeting discussed Kyiv's request for air and missile defence systems and technology to shoot down the drones.
Mr Kuleba tweeted that he informed Mr Lapid about the “unspeakable suffering, loss of life and destruction caused by Russian missiles and Iranian-made drones”.
Mr Lapid repeated Israel's support for Ukraine during the call, according to his office.
Although it has condemned the Russian invasion, Israel has said it would not supply Kyiv with weapons, with Defence Minister Benny Gantz telling EU ambassadors earlier this week that this was due to “a variety of operational considerations”.
“Israel has a policy of supporting Ukraine via humanitarian aid and the delivery of life-saving defensive equipment,” Mr Gantz said.
However, Israel has limited its humanitarian assistance for Ukraine, citing its desire to continue to co-operate with Moscow over war-ravaged neighbour Syria and ensure the well-being of Russia's Jews.
Most recently, Israel offered to help Ukraine to develop air attack alerts for civilians.
Russia has launched dozens of “kamikaze” drone attacks on Ukraine, damaging energy infrastructure. Kyiv says they are Iranian-made Shahed-136 unmanned aerial vehicles.
Tehran denies supplying the drones to Moscow and the Kremlin on Tuesday rejected reports that its forces had used Iranian drones to attack Ukraine.
However, Washington said Iran's denial was a lie.
On Wednesday, Ukrainian Ambassador Yevgen Kornichuk told Reuters that Israel's offer to develop an early warning system was “not relevant any more”.
He confirmed the authenticity of an embassy letter, leaked to Israel's Walla news agency, urgently requesting to buy Iron Beam, Barak-8, Patriot, Iron Dome, David's Sling and Arrow interceptors from Israel.
Iron Beam is years away from being operational, Israel said. Patriot is a US-made system deployed in Israel while Barak-8 was jointly developed by Israel and India.