Armenia still must amend its constitution to remove a reference to Nagorno-Karabakh, Azerbaijan's ambassador to Britain said.

The leaders of Armenia and Azerbaijan shook hands as they joined President Donald Trump at the White House on Friday for a peace summit where they signed an agreement aimed at ending decades of conflict.

Armenia said it would give the U.S. exclusive development rights to a transit corridor through its territory, which will be named the Trump Route for International Peace and Prosperity.