President Trump said early Thursday that he would not have allowed Russia to annex Crimea, stressing that it happened on "Barack Obama's watch."

"That's an interesting question," he said when asked at the end of a tumultuous NATO summit in Brussels if he would recognize Russia's annexation of Crimea. "Long before I got here, President Obama allowed that to happen. That was on his watch, not on my watch.

"People like to say, 'Oh, Crimea,' but the fact is they built bridges to Crimea, they just opened a big bridge that was started years ago. They built, I think, a submarine port, substantially added billions of dollars," he added.

"That was on Barack Obama's watch, that was not on Trump's watch," the president said. "Would I have allowed it to happen? No. I would not have allowed it to happen. But he did allow it to happen so that was his determination.

"What will happen with Crimea from this point on? That, I can't tell you. But I'm not happy about Crimea," he said.

Trump made the comments at a press conference after a contentious summit in which in attacked NATO members over defense spending, calling for it to be raised to 4 percent of nations' gross domestic product.

He also signed a joint document at the summit harshly critical of Moscow.

Trump will meet with Russian President Vladimir Putin in Helsinki, Finland on Monday.

Trump said before the NATO summit that the Putin meeting may be the easiest of his foreign trip.

"We'll see," Trump said on Thursday when asked if he'd raise the annexation of Crimea with Putin.

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