US President Donald Trump has been handing out his cellphone number to world leaders and urging them to call him directly, an unusual invitation that breaks diplomatic protocol and is raising concerns about the security and secrecy of his communications.

Trump has urged leaders of Canada and Mexico to reach him on his cellphone, according to former and current US officials with direct knowledge of the practice.

Trump also exchanged numbers with French President Emmanuel Macron when the two spoke immediately following Macron's victory earlier this month, according to a French official, who would not comment on whether Macron intended to use the line.

The notion of world leaders calling each other up via cellphone may seem unremarkable in the modern, mobile world.

But in the diplomatic arena, where leader‑to‑leader calls are highly orchestrated affairs, it is another notable breach of protocol for a president who has expressed distrust of official channels.

US Presidents generally place calls on one of several secure phone lines, including those in the White House Situation Room, the Oval Office or the presidential limousine.

Source: AP