KYIV, Ukraine, May 28, 2025 (BSS/AFP) - Ukrainian President Volodymyr Zelensky has called for a three-way summit with Donald Trump and Vladimir Putin as he seeks to force Moscow to halt its three-year invasion.

Russian President Putin rejected calls to meet Zelensky in Turkey earlier this month and the Kremlin has said a meeting between the two leaders would only happen after some kind of "agreement" is reached.

The US president, meanwhile, has expressed frustration at both Putin and Zelensky for not yet striking a deal to end the war.

"If Putin is not comfortable with a bilateral meeting, or if everyone wants it to be a trilateral meeting, I don't mind. I am ready for any format," Zelensky said in comments to journalists on Tuesday that were published on Wednesday.

The Ukrainian leader said he was "ready" for a "Trump-Putin-me" meeting, and also urged Washington to hit Moscow with a package of hard-hitting sanctions on its banking and energy sector.

"We are waiting for sanctions from the United States of America," Zelensky said.

"Trump confirmed that if Russia does not stop, sanctions will be imposed. We discussed two main aspects with him -- energy and the banking system. Will the US be able to impose sanctions on these two sectors? I would very much like that."

The Ukrainian leader had previously appeared to express frustration at Washington for not having announced fresh sanctions on Moscow after Russia rejected a coordinated Western appeal for an immediate ceasefire.

Hours after Zelensky spoke, Ukraine unleashed one of its largest ever drone barrages on Russia, firing almost 300 drones at the country, according to the defence ministry in Moscow.

Russian officials reported only minimal damage from the attacks.

On the battlefield, Zelensky said that Russia was "amassing" more than 50,000 troops on the front line around the northeastern Sumy border region, where Moscow's army has captured a number of settlements as it seeks to establish what Putin has called a "buffer zone" inside Ukrainian territory.

Zelensky also said that Ukraine is yet to receive a promised "memorandum" from Russia on its demands for a peace deal.