Speaking at the UN General Assembly on Tuesday, Trump asked whether he should "annihilate the Islamic Republic" or offer it a deal to rebuild before telling reporters that US and Iranian officials had met on the sidelines. Most of Iran's delegation walked out during his speech.
The agreement will enable the US to expand its military presence on Greenland through the modernisation and enlargement of its current Pituffik Space Base and the establishment of new defence areas at Narsarsuaq and Mestersvig.
Tehran's decision-making structures appear gripped by a war of words as conflicting reports emerge on Tuesday about an agreement to reopen the Strait of Hormuz within seven days if the US eases its military pressure.