File Photo: U.S. President Donald Trump (L) and British Prime Minister Theresa May (R) attend the handover ceremony of the new NATO headquarters during a one-day NATO Summit, in Brussels, Belgium, May 25, 2017. (Xinhua/Ye Pingfan)

WASHINGTON, Dec. 19 (Xinhua) -- White House spokesperson Sarah Sanders said here Tuesday that U.S. President Donald Trump has accepted an invitation by British Prime Minister Theresa May to visit her nation and the president has been "tough" on Moscow.

According to the White House, Trump called May earlier on Tuesday, the first since their twitter dispute, and the two leaders "exchanged holiday greetings and warm wishes for Christmas and the New Year." They also discussed next steps in forging peace in the Middle East.

The "special relationship" between Trump and May has been questioned in recent weeks following the U.S. president's retweeting of several videos clips posted by a British far-right group. May said Trump's decision was wrong and Trump responded by asking her to take care of her nation. British parliament members have urged May not to invite Trump for a state visit next year.

Speaking of May's invitation, Sanders said it has been "extended and accepted," adding that the White House is working with the British side "to finalize the details, which we expect to announce soon."

Asked why Trump did not use harsh rhetoric against Russia in his speech on the national security strategy on Monday, Sanders said Trump and the White House have always been "tough" on Russia.

"The president has weighed in on Russia and his feelings on that a number of times. The policy and the strategy put forth in that very detailed paper was that of the president and it reflects his views," she said.

She added that Trump "has been clear what his position is. We've been tough on Russia, we've put sanctions on Russia, we've imported energy, and impacted them in a big way. The president has not been soft in this process."

In the national security strategy and the speech, the Trump administration labeled Moscow as the United States' "competitor" and "rival power" seeking to undermine the Washington-led international order and U.S. interests. Russia has denied such an allegation repeatedly.