US Vice-President JD Vance will join his wife Usha in travelling to Greenland on Friday, a visit that follows Donald Trump's threats to take over the island. The couple will go to the Pituffik Space Base to receive a briefing on Arctic security issues and meet members of US forces stationed there, according to the White House. Usha Vance had planned to travel to the Danish territory on a cultural visit before her husband announced his plans.