Helsinki, Finland (CNN) President Donald Trump plans to raise the issue of election meddling in his summit with Russian President Vladimir Putin, but he told officials during his UK visit that he already knows Putin will again deny interference in the 2016 election -- and doesn't expect much progress, according to a source familiar with the discussion.

"I will absolutely bring that up. I don't think you'll have any, 'Gee, I did it. I did it. You got me.' There won't be a Perry Mason here, I don't think, but you never know what happens, right? But I will absolutely, firmly ask the question," Trump said. "And hopefully, we'll have a very good relationship with Russia."

Instead, the US President is setting his sights on establishing a new Strategic Arms Reduction Treaty (START) between the United States and Russia to continue decades of progressive nuclear disarmament between the two countries, the source told CNN. The source said Trump has been fired up about making progress on extending the US and Russia's denuclearization treaty, now known as New Start which is set to expire in 2021.

Trump sees progress on an arms control treaty as the likeliest area of progress for the Trump-Putin summit, the source said.

Read More