Panama has alerted the United Nations - in a letter seen by Reuters on Tuesday - to U.S. President Donald Trump's remarks during his inauguration speech, when he vowed that the United States would take back the Panama Canal.

Trump's executive order called for an immediate withdrawal from the Paris Agreement. The agreement requires one year notice, but there's room for interpretation.

President Donald Trump ordered the U.S. to withdraw from the Paris climate agreement on Monday, once again placing the world's top historic emitter of greenhouse gases outside the global pact aimed at pushing nations to tackle climate change.

U.S. withdrawal from the world's primary climate pact will have a bigger impact - in the U.S. and globally - than the country's first retreat in 2017, analysts and diplomats told Reuters. One of President Donald Trump's first acts on returning to office on Monday was to quit the Paris Agreement as part of his plans to halt U.