KYIV, June 12 — Ukraine is seeking an additional $20 billion in military funding from its allies to cement what it sees as its current battlefield advantage over Russia, a Ukrainian defense source said on Friday.

The request will be made next Thursday at a meeting of the Ukraine Defense Contact Group, an alliance of more than 50 countries also known as the Ramstein group that provide financial and military aid for Kyiv.

Russia’s advances have slowed this year — effectively grinding to a halt last month — as Ukrainian mid-range drone strikes have harmed its supplies and logistics for the front line.

Long-range drone strikes are meanwhile inflicting pain on Russia’s energy sector.

In recent weeks, Ukrainian military commanders have said the dynamics on the battlefield have given them a window this year to bring Russia to the negotiating table on more favorable terms.

Robert Brovdi, the commander of Ukraine’s drone forces, told Reuters that his strategic aim was to force Russia to pull its troops back from the frontline by destroying their supply lines and logistics with escalating drone attacks.

To achieve that, he said, Ukraine needed money.

“The production capabilities, the quality of drones and the number of crews operating in Ukraine are enough to inflict devastating blows on the Russian economy, clog their logistics and kill personnel,” Brovdi said.

Zelenskiy said last month that he wanted to press ahead before the onset of winter with peace talks with Russia, which have stalled in recent months, to capitalize on the improvement in Kyiv’s strategic position.

However, Putin said last week that Russian forces were still advancing every day and he saw no need for such talks.

He said there was no risk to Russia’s economy, though he acknowledged Ukrainian strikes were causing harm.

Ukraine’s plan to request additional funds was first reported by Politico.

At the meeting next week, some allies will each be asked to contribute between $2 billion and $6 billion to reach the $20 billion target, either in the form of aid or a loan, the source said.