The Kremlin said on Thursday that it would be Ukrainians who suffered if Britain or other Western countries supplied fighter jets to Kyiv, and said Moscow would press on with its military campaign in Ukraine regardless of what arms the West sent.

During a visit to London on Wednesday, Ukrainian President Volodymyr Zelenskiy called on Britain to send advanced fighter jets to Kyiv as part of the next stage of Western arms supplies to help Ukraine's forces.

Kremlin spokesman Dmitry Peskov said that any delivery of advanced NATO-standard fighter jets would only bring pain and suffering to Ukrainians and criticised NATO countries taking a more "direct" role in the conflict.

"This is nothing more than the growing involvement of the United Kingdom, Germany and France in the conflict between Russia and Ukraine," Peskov told reporters.

"The line between indirect and direct involvement is gradually disappearing. One can only express regret in this regard, and say that such actions ... lead to an escalation of tension, prolong the conflict and make the conflict more and more painful for Ukraine," he added.

If the West agrees to Zelenskiy's calls for fighter jets, he Peskov said, Russia will not be deterred and will continue with what it calls its "special military operation" in Ukraine until Moscow has met its objectives. (Reporting by Reuters Editing by Gareth Jones)