U.S. President Donald Trump has thanked Albania for expelling Iran's ambassador to Tirana and another diplomat for alleged national security reasons.



Trump thanked Prime Minister Edi Rama in a letter for his "steadfast efforts to stand up to Iran and counter its destabilizing activities and efforts to silence dissidents around the globe," according to the U.S. Embassy in Tirana.



The diplomatic mission published the letter, dated December 14, on its Twitter page on December 20.



The previous day, Albanian announced it had expelled the two diplomats, saying they were suspected of "involvement in activities that harm the country's security" and for "violating their diplomatic status."



Precise reasons for the expulsion were not given.



It was also not clear when the pair were expelled, but an Albanian Foreign Ministry spokesman was quoted as saying that the expulsions followed talks with other countries, including Israel.



Iran blamed Israel and the United States for putting pressure on Albania and said it had respected Albanian laws.



Foreign Ministry spokesman Bahram Ghasemi said that Albania has become “an unintentional victim of the United States, Israel, and some terrorist groups," according to the official IRNA news agency.



Ghasemi said the United States and Israel are working to destroy relations between Iran and European countries, and that Albania should not allow other states to dictate its relations with Tehran.



Trump's letter said the expulsion "exemplifies our joint efforts to show the Iranian government that its terrorist activities in Europe and around the world will have severe consequences."



His national-security adviser, John Bolton, tweeted that Albania’s move signaled to the Iranian leadership that “their support for terrorism will not be tolerated.”



And U.S. Secretary of State Mike Pompeo in a statement described the diplomats as "two Iranian agents who plotted terrorist attacks in Albania."



News agencies identified Iran’s ambassador to Tirana as Gholamhossein Mohammadnia.



One unconfirmed Albanian report suggested the expulsions were linked to an alleged plot to attack a World Cup qualifying match in 2016 between Muslim-majority Albania and Israel two years ago in Albania.

About 20 people were arrested in Albania and Kosovo following the match.



Another report linked Albania’s move to threats to an Iranian exile opposition group -- the Mujahedeen-e-Khalq (MEK). An estimated 2,000 members of the group have moved from Iraq to Albania in 2013.

With reporting by AFP, AP, The Jerusalem Post, and Reuters