U.S. President Donald Trump has been handing out his mobile phone number to world leaders, urging them to call him directly.
It is an "unusual invitation" that breaks diplomatic protocol and raises concerns about the "security and secrecy" of the U.S. top leader's communications, the Associated Press reported on Tuesday.
The report said among the leaders who have been given the president's phone number are Canadian Prime Minister Justin Trudeau and Mexican President Enrique Pena Nieto.
Trudeau is the only one who has taken this advantage to speak directly with Trump via cellphone so far.
France's new President Emmanuel Macron also exchanged numbers with Trump after Macron's election victory, a French official told the AP.
The report came just days after Trump wrapped up his first foreign trip as president, which took him to the Vatican, Israel, Saudi Arabia and Italy.
In need of considerable advance planning, calls between country leaders are generally highly orchestrated and classified diplomatic affairs.