President of Ukraine Volodymyr Zelensky has said that while some western sanctions had already dealt a severe blow to the Russian economy, they "have not really influenced the Russian position."

He said this on Tuesday at the FT's Global Boardroom conference, the Financial Times reported.

According to him, Moscow was constantly finding ways to circumvent sanctions. He also suggested that some western governments were already tiring of the economic fallout from sanctions on Russia and were looking for ways to soften the impact to protect their own commercial interests.

Zelensky said that the result of the sanctions will be able to see over the time. At the same time, he called for the imposition of sanctions in full immediately. "We need to switch off all Russian banks from SWIFT," he said.

"They are supporting Ukraine but also checking what can be done to weaken sanctions so business doesn't suffer," Zelensky said. On UN-led talks to restore access to Ukrainian Black Sea ports, Zelensky was willing to back the idea of a maritime corridor to enable grain exports from Ukrainian ports as long as no access was given to Russian ships. There was no need for a dialogue with Moscow to resolve the blockade given that the only threat to world food supplies was coming from Russia, he said.

"Russia has stolen a certain amount of our grain, and took it on their ships abroad, their ships entered some countries, but we were able to find out this information… But you understand the gravity of the precedent," he said.

He once more appealed for western military support to restore his country's territorial integrity. "We are inferior in terms of equipment and therefore we are not capable of advancing," he said.

Zelensky said pushing Russian forces back to positions occupied before the February 24 invasion would amount to a "serious temporary victory" for Ukraine but full sovereignty over its territory remained his ultimate goal.

He said "victory must be achieved on the battlefield." But he also insisted he was open to peace talks despite atrocities committed by Russian troops during their 100-day onslaught.

According to him, any war should be ended at the negotiating table. However, peace negotiations would have to be face to face with President Vladimir Putin, because there was "nobody else to talk to" but the Russian leader. Zelensky hit out at what he saw as attempts by some western allies to explore the terms of a ceasefire without involving Kyiv. "We need abiding interest from the west, western support for Ukraine’s sovereignty. There cannot be talks behind Ukraine's back anytime. How can we achieve a ceasefire on the territory of Ukraine without listening to the position of this country? This is very surprising," he said.

He said his allies could do more to bring Russia to the negotiating table by supplying Ukraine with arms and by toughening economic sanctions on Moscow, including a complete oil and gas embargo.

According to him, they should not be mere mediators, but should be ensuring that Moscow ended its hostilities and would honour any ceasefire.

Zelensky took issue with French president Emmanuel Macron's warnings to the west not to treat Russia in the spirit of "humiliation." Macron knew very well about Russia's failure to implement earlier peace agreements under the so-called Minsk process which failed to end the fighting in Donbas since 2014, Zelensky said. "I don't really understand…   humiliating Russia. For eight years they have been killing us. What are we talking about here?" he said.

By contrast, Zelensky said it was "great news" that British Prime Minister Boris Johnson had survived a no-confidence vote by Conservative MPs on Monday night. "I am glad we have not lost a very important ally."