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

“I do think we need a comprehensive strategy for success in this war and that is what President Zelenskyy says he is bringing, so we are very much looking forward to sitting down and talking that through and President Biden is eager for that conversation,” Sullivan said.

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

Sullivan said the U.S. also aimed to prepare a “substantial” support package with various capabilities by the end of the month as it worked to prevent a significant Russian breakthrough in Ukraine’s east.

Russian forces have been gaining ground in parts of eastern Ukraine including around Pokrovsk, an area that Sullivan said was of “unique concern.”

The capture of the transport hub could enable 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, Kyiv has pleaded for long-range weapons to strike deeper into Russian territory.

Sullivan said the matter was the subject of “intense consultations” among allies and partners, and would also be discussed between Biden and Zelenskyy.