Zelenskiy, in his nightly video address on Monday, issued a fresh plea for air defences to protect against Russian strikes on cities and infrastructure and called on Kyiv's allies to show the same unity they displayed in helping Israel fend off Iranian attacks.

Zelenskiy noted three sectors where Ukraine's forces face difficult situations in standing against Russian onslaughts: Chasiv Yar, west of the destroyed Russian-held town of Bakhmut in the east and Pokrovsk and Kupiansk, further west and north.

Zelenskiy said reports were presented on supplying arms and electronic warfare systems and ways to protect infrastructure hit for weeks by Russian missile and drone attacks.

Also heard were intelligence reports on new Russian offensives that he has predicted will soon be launched.

"This is about what we must prepare for - all forms of enemy action," Zelenskiy said.

"It is clear that the madness in the Kremlin is still strong and the occupiers will try to intensify their advances. We will respond."

Russian forces have made small advances in recent weeks, securing control of villages in eastern Donetsk region since recapturing the key town of Avdiivka in February.

The president again lauded what he described as "unity" in helping Israel defend against Iranian air attacks last weekend.

"Israel is not a member of NATO ... and no one was drawn into the war," he said.

"They simply helped save lives. Shaheds (drones) in the skies of Ukraine sound just like in the skies of the Middle East. Ballistics strike the same everywhere if not shot down."

He has called for "political will", especially from the United States, where an aid package remains blocked in Congress.

US House of Representatives Speaker Mike Johnson is expected to decide this week on how to handle President Joe Biden's request for billions of dollars in security assistance for Ukraine and other US allies.

Johnson has declined to allow the Republican-controlled House to vote on the measure already passed by the Senate.

Foreign Minister Dmytro Kuleba earlier told a Black Sea security conference Ukraine needed additional Patriot and other air defence systems.

Western allies have been reluctant to send additional air defences to Kyiv, while Ukraine needs 26 Patriot systems to cover the country's territory in full. Germany has pledged to deliver another system following calls from Kyiv.

Kuleba met his Norwegian counterpart Espen Barth Eide in Kyiv to coordinate efforts to provide Patriots promptly.

Australian Associated Press