Sri Lanka, Jan. 20 -- US President Donald Trump has described the UK's deal to hand the Chagos Islands to Mauritius and lease back a key military base as an "act of great stupidity", months after he endorsed the move.

The UK signed the £3.4bn ($4.6bn) agreement in May, under which it would retain control of a UK-US military base on the largest of the islands, Diego Garcia.

Previously US Secretary of State Marco Rubio hailed it as a "monumental achievement", but on Tuesday, Trump called the deal an "act of total weakness" and said it was among a "very long line of National Security reasons" for his efforts to acquire Greenland.

A UK government spokesperson said it would "never compromise on our national security".

In a post on his...