Denmark has called in the US ambassador over a report that Washington is stepping up its espionage of politicians in Greenland and Copenhagen.

Officials summoned the American ambassador to express its displeasure after the Trump Administration was said be ratcheting up surveillance.

Director of National Intelligence Tulsi Gabbard's office last week sent a "collection emphasis message" to the CIA, NSA and other spy agencies directing them to collect intelligence about Greenland's independence movement and identify potential allies there and in Denmark who support Trump's objective of taking over the island,