US President Joe Biden to discuss Ukraine’s war strategy with President Volodymyr Zelensky this month and Washington is working on a “substantial” new aid package, White House National Security Adviser Jake Sullivan said Saturday.

Zelensky said he wants to present a “victory plan” that could push Russia to end the war in Ukraine diplomatically to Biden and his two potential successors.

“I think we need a comprehensive strategy for success in this war, and that’s what President Zelensky says he brings, so we’re very much looking forward to sitting down and talking about that, and President Biden is willing to have that conversation,” Sullivan said.

He spoke via video link at the Yalta European Strategy conference organized by the Victor Pinchuk Foundation in Kyiv.

Sullivan said the US also aims to prepare a “substantial” multi-capability support package by the end of the month as it works to prevent a major Russian offensive in eastern Ukraine.

Russian forces have gained ground in parts of eastern Ukraine, including the Pokrovsk region, an area Sullivan said was of “unique concern.”

Seizing the transport hub could allow Moscow to open new lines of attack and complicate Ukrainian logistics.

As Russia has stepped up its missile attacks on Ukraine’s critical infrastructure this year, Kiev has called for long-range weapons to strike deeper into Russian territory.

Sullivan said the issue had been the subject of “intense consultations” among allies and partners and would also be discussed between Biden and Zelensky.