Nobody has been tougher on Russia than I have: Trump

US President Donald Trump has said 'nobody has been tougher' on Russia than him even as he expressed hope that having a good relationship with his Russian counterpart Vladimir Putin would be a 'great thing'.

Trump's comments came on Tuesday during a meeting with leaders of the Baltic states -- Estonia, Latvia and Lithuania -- a day after the White House confirmed the president invited Putin to the Oval Office for a potential meeting.

"I think we'll be able to have great dialogue, I hope. And, if we can't, you'll be the first to know about it. Nobody's been tougher on Russia than I have," he said.

Trump was asked if he considered Putin a friend or a foe.

"It's a real possibility that I could have a good relationship. And remember this: Getting along with Russia is a good thing. Getting along with China is a good thing. Getting along with other countries, including your three countries is a good thing, not a bad thing," Trump told reporters at a White House joint news conference with Baltic leaders.

"So I think I could have a very good relationship with Russia and with President Putin. And if I did, that would be a great thing. And there's also a possibility that won't happen. Who knows?" he said.

Trump noted that the US is "very strong" on energy, which he said, is not good for Russia.

"We're essentially now energy-independent. We're an exporter of energy. That is not a positive for Russia. But it's certainly a positive for the United States," he said.

His administration, Trump said, has just passed a USD 700 billion military budget.

"Next year, USD 716 billion, the largest ever passed. We are going to have a military stronger than we've ever had before, by far. Now, that's not exactly a great thing for Russia. But that's the way it is. We're going to have the strongest military that we ever had," he said.

The US President reiterated the non-payment of bills by some NATO member countries.

"NATO was delinquent. They were not paying their bills. They were not paying, a lot of states, as we discussed. They were not -- they were not paying what they should be paying," he said.

Trump said since he came in, many billions of dollars additional have been paid by countries that weren't paying, and now they're paying.

"And they will have to pay more, frankly. They're going to have to pay more," Trump said.

"So there are many things that I've done, and not only the 60 diplomats. Germany did four, France did four, we did 60. There's nobody been tougher on Russia," he said on the US' expulsion of 60 Russian diplomats in response to a chemical attack on a former Russian spy in the UK.