"We'll be talking about peace. We may even talk about saving millions of dollars on weapons...we are building a force like nobody's ever seen before," he reporters when asked about his meeting with Putin next month.
This would be Trump's first summit with Putin, even though the leaders have met twice in the last one and half years.
The announcement of the meeting had followed after President Putin met US National Security Adviser John Bolton, who was in Moscow this week to lay the groundwork for the summit.
"Perhaps the world can de-escalate with China, Russia...may be the world can somewhat deescalate. That would not be a bad thing. But I think having a relationship with China, Russia...it's a good thing," Trump said.
Asked about a lifting of sanctions on Russia, Trump appeared to be non-committal.
"We'll see what Russia does. We're going to be talking to Russia about a lot of things. We're going to be talking to them about Syria," he said.
Responding to a question on NATO, Trump reiterated that other countries had to spend more.
"NATO is very interesting, we'll see what happens there. Germany has to spend more money, Spain, France, it's not fair what they've done to the United States," he said, adding that the US is paying much more disproportionately to anyone else.
From the beginning of his presidential campaign, Trump has insisted that he wants a better relationship with Russia, asserting that it will be good for the US and for the world.
However, he has been facing backlash from the Opposition Democrats and the think-tank community who believe that Russia under Putin interfered in the 2016 presidential election. Moscow has denied the allegations.