(CNN) As the top US diplomat in Ukraine was working to release frozen security assistance to Kiev, he discovered the focus back in Washington was elsewhere: President Donald Trump's interest in buying Greenland.

Speaking to impeachment committees last month, Ambassador Bill Taylor described difficulty in convening a meeting of top-level Cabinet officials with Trump to discuss the Ukraine assistance, which was put on hold over the summer.

Part of the issue was logistics, he said. But it also came as national security officials inside the White House were scrambling to contain Trump's Greenland idea.

"It turns out, Mr. Chairman, that those principals, as we call them, were on different trips at different times," he said during his closed-door deposition, a transcript of which was released on Wednesday . "I think this was also about the time of the Greenland question, about purchasing Greenland, which took up a lot of energy in the NSC."

Trump raised the idea of purchasing Greenland -- an autonomous Danish territory -- on multiple occasions over the past year. It was first reported in mid-August that he was interested. After the Danish government shot the idea down, Trump canceled a planned trip to Copenhagen.

Read More