"That's a horrible thing that happened," he said. "It's disgusting and disgraceful but Putin and Russia say they didn't do it, the other side said they did, no one really knows who did it, probably Putin knows who did it. Possibly it was Russia but they are totally denying it."
Trump was responding to a question from CNN noting that the U.S. government assesses that the several points of available evidence all point to Russia.
The question from CNN came after Trump was asked on MSNBC Wednesday about a new report
from Dutch investigators that Malaysia Airlines Flight 17 was shot down by a Russian-made rocket and warhead -- and asked what he would do as president to hold Russia accountable.
U.S. intelligence determined with confidence soon after the attack that a Russian-supplied missile brought the jet down from territory controlled by pro-Russian separatists. U.S. intelligence continues to stand by that assessment.
"They say it wasn't them," Trump said. "It may have been their weapon, but they didn't use it, they didn't fire it, they even said the other side fired it to blame them. I mean to be honest with you, you'll probably never know for sure."
Trump later said the culprit was "probably" Russia and pro-Russian fighters, but he said the U.S. needs to focus on its own problems right now and not "get involved" in overseas conflicts, even one as "horrible" as this.
"I think it is horrible," Trump said of the incident. "But they're saying it wasn't them. The other side says it is them. And we're going to go through that arguing for probably for 50 years and nobody is ever going to know. Probably was Russia."
Trump said regardless, it's time to turn the page.
"It's a long ways away. We have to get back to making America great again," he said. "It's terrible, but we really probably won't know for sure. And you'll probably never find out. There are only a few people that know. And you know one of them could be (Russian President Vladimir) Putin, frankly, and we know one thing: He's not going to be talking about it."
The Republican presidential front-runner's remarks seem to bolster the Russian line of response to the report, which was released on Tuesday, and previous accusations that the government could have been involved in the missile launch.
Early in the investigation, a senior defense official told CNN
that the U.S. intelligence community believed pro-Russian separatists were behind the explosion and could not have operated the Russian missile system without Russian training.
Russian participants in the Dutch investigation have denied there is conclusive evidence about the origin of the missile.