Meanwhile, Donald Trump has continued to argue that NATO has become obsolete. Speaking to ABC’s George Stephanopoulos on Sunday, Trump said NATO had been unable to stop Russia’s annexation of Crimea last year. Trump also said that, if elected, he might formally recognize Russia’s takeover of Crimea.

Donald Trump: “I’m going to take a look at it. But, you know, the people of Crimea, from what I’ve heard, would rather be with Russia than where they were. And you have to look at that also. Now, that was under—just so you understand, that was done under Obama’s administration. And as far as the Ukraine is concerned, it’s a mess. And that’s under the Obama administration, with his strong ties to NATO.”

Some Democratic Party officials have suggested Russia is behind the release of Democratic Party emails in an effort to help sway the election to Trump, but no evidence to back the claim has been provided.