Washington (CNN) Sen. Tom Cotton says he raised the idea of buying Greenland with the White House well before the issue became public last week, a proposal that ultimately caused a diplomatic spat between President Donald Trump and the Danish Prime Minister .

The Arkansas Republican discussed purchasing the territory of Greenland with Denmark's ambassador to the US last year and subsequently floated the idea to President Donald Trump, a senior Senate aide confirmed to CNN on Thursday.

Those conversations occurred prior to Trump postponing his upcoming trip to Denmark via Twitter this week after Danish Prime Minister Mette Frederiksen disputed the idea of a Greenland sale as "absurd."

The White House did not immediately respond to CNN's request for comment.

Despite the controversy and questions about the seriousness of such a proposal, Cotton said he still believes that buying Greenland would be in the United States' best interest.

"In the last few years, China has repeatedly tried to gain a strategic foothold in Greenland, by offering to buy a former US military base there and through a financing scheme for airport construction. Purchasing it would keep it out of the hands of both the Chinese and the Russians. It is rich in national resources with untold economic potential and already extremely important to US national security," he told CNN.

"There's a reason why -- so you're joking -- but I can reveal to you that several months ago I met with the Danish ambassador, and I proposed they sell Greenland to us," he responded, according to the Arkansas Democrat Gazette. "It's obviously the right decision for the United States, and anyone who can't see that is blinded by Trump derangement."

Cotton, who is widely regarded as a foreign policy hawk, has routinely offered his advice to the President on a wide array of national security issues. Trump confirmed his interest in buying Greenland on Sunday, though at the time he suggested his now-postponed trip to Denmark was not related.

"We are good allies with Denmark. We protect Denmark like we protect large portions of the world, and the concept came up," the President said on Sunday. "Strategically it's interesting, and we would be interested, but we will talk with them a little bit."

Frederiksen was not amused, telling the newspaper Sermitsiaq, "Greenland is not for sale. Greenland is not Danish. Greenland belongs to Greenland."

"I strongly hope that this is not meant seriously," she said, calling the conversations "an absurd discussion."

Trump has on multiple occasions brought up buying Greenland from the Danish government and the White House counsel's office has looked into the possibility, two sources told CNN last week.

Some Democrats, including 2020 front-runner Joe Biden, have mocked the suggestion of purchasing Greenland but a senior Senate aide told CNN that the idea is no laughing matter.

"The idea is self-recommending. Do the Democrats regret our purchase of Alaska?" the aide said.

A Republican aide echoed Cotton's assertion that buying Greenland would provide the US with strategic advantages over China and Russia but said Trump's decision to abruptly cancel his trip to Copenhagen may have "blown up" any progress made behind the scenes in recent months.

Additionally, multiple Republican aides told CNN that they never imagined a situation where the US would have to address tensions with Denmark, which has been a stable partner and ally for years.