New York, Sept. 22 -- US President Donald Trump on Tuesday joined Danish Prime Minister Mette Frederiksen and Greenland Prime Minister Jens-Frederik Nielsen to sign an agreement to strengthen defence and Arctic security cooperation, ending months of diplomatic friction.

Ahead of signing the pact on the sidelines of the UN General Assembly in New York, President Trump expressed optimism about the future of the partnership.

"We're going to have a tremendous relationship, a secure relationship, and we look forward to it... This was long in the making," he said.

This comes after Trump said on Saturday he had reached what he described as an "Infinite Life" Agreement with Denmark and Greenland, claiming the pact gives the United States perma...