"We attacked a certain number of their refineries; they have a problem. When they started rebuilding and saw the lines of cars, they redistributed the quantities to other refineries," Zelensky said during a meeting with a small group of journalists in Kyiv.

"Therefore, our task is absolutely clear – to continue our work in other plants that have started to increase the amount, especially of diesel. And we simply have to work on it every day," added Zelensky. Ukraine has reportedly released gas from 21 of 38 major Russian oil refineries across the country since January, according to the BBC.

Ukraine aims to cripple Russia's oil industry and cut off a key source of revenue for Moscow's war machine. Zelensky believes that long-term oil shocks, plus US sanctions and a mega-loan to Kiev from the EU funded by frozen Russian assets, could push Kremlin chief Vladimir Putin to the negotiating table.

Zelensky said that while Kiev wants allies to continue supplying long-range missiles, expanding domestic long-range capabilities is a key priority. He added that Ukraine carries out 90 percent of its deep strikes on Russia with its own drones and long-range cruise missiles, but sometimes Kiev uses British Storm Shadow missiles and French Scalp missiles to hit targets.

"Long range presence expected to expand"

"Long-range capabilities are a component of independence and will be the biggest component for securing peace," Zelensky added in an evening address to the nation on Monday.

"All deep strike targets must be fully concluded by the end of the year, including expanding our long-range presence."

He earlier met with Ukrainian long-range weapons makers and ordered the government to conclude 57 long-term contracts with makers of key drones and long-range missiles by the end of the year.

Ukraine is also stockpiling its latest domestic cruise missiles, the Flamingo, in order to launch a [...] massive strike on Russia by the end of the year," Zelensky warned.

"We must work every day to weaken the Russians. Their money for the war comes from oil refining," the Ukrainian president added.

Zelensky said the strikes on Russian energy facilities are just part of a pressure campaign he hopes can force Russian President Vladimir  Putin to end his full-scale invasion.

A key part of frozen Russian assets

A key part of that package, Zelensky said, is for the EU to unfreeze 140 billion euros of Russian assets held in the bloc, to be used as a huge reparation loan to help Ukraine — and he wants the EU to give the green light for that at a December leaders' summit.

"For Putin, the scariest part of the whole story about Russian assets for Ukraine is that Europe would send a signal that there is no point in continuing its war of attrition against Ukraine, because there will be no financial attrition," Zelensky said.

Zelensky said that he is very grateful for the US sanctions against the Russian oil companies Lukoil and Rosneft and that he now hopes that US President Donald Trump, during his meeting with Chinese leader Xi Jinping this week, will be able to convince Beijing to buy less oil from Moscow.

"This is all in the right direction to put pressure on Russia to be ready to end the war — sanctions, weapons, use of funds," Zelensky said.