It started as a plea for help amid the devastating aftermath of Hurricane Maria, but rapidly escalated into an unprecedented media war between a city mayor and the most powerful man on Earth.

For almost a fortnight the world's press has been gripped by the increasingly acrimonious exchanges between President Donald Trump and Carmen Yulin Cruz, the mayor of Puerto Rico’s capital city San Juan.

The flash point was a dispute over how aid was being distributed across the hurricane-ravaged US territory. The intervening days have seen Mr Trump launch personal attacks on Mrs Cruz on Twitter, followed by the bizarre spectacle of the mayor wearing a T-shirt emblazoned with "nasty" - one of the President's epithets for her - during a TV interview.

Mr Trump is no stranger to social media controversies nor using Twitter to excoriate his opponents, as "crooked" Hillary Clinton, the "fake" news media and "overrated" Meryl Streep can all attest. Often the recipients of his ire choose to maintain a dignified silence or attempt to rise above it.

Yet in Mrs Cruz, Mr Trumps appears to have met an opponent who is just as pugnacious and adroit in her use of the media as the billionaire former reality TV star.

This is how the extraordinary episode has unfolded thus far.

Hurricane Maria and a stalled relief effort

Hurricane Maria flattened Puerto Rico as it barreled through the Caribbean last month, leaving the majority of its 3.4 million population without electricity or access to clean water.