Washington, United States: US President-elect Donald Trump arrived at the White House Friday for his final meeting with outgoing leader Barack Obama, before heading to the Capitol for his swearing-in ceremony.

Obama and First Lady Michelle greeted the Republican billionaire leader-in-waiting and his wife Melania on the steps of the presidential mansion. 

"Mr President-elect, how are you?" Obama asked.

The two couples headed inside for traditional tea and coffee with their vice presidents and congressional leaders -- but not before a mini-commotion caused by an unexpected gift from the incoming first lady to her predecessor.

After a hesitant embrace, Melania presented Michelle with a large box from the high-end jeweler Tiffany's -- located next door to Trump Tower in New York -- in the store's iconic blue tone, which complemented her own outfit.

An awkward sequence ensued, with the world looking on, as Michelle spun around, seemingly perplexed about where to place the surprise gift while the four posed for a photograph.

Neither of the Marines standing guard beside them were authorized by protocol to break their salute to hold the box, and the snafu was only resolved when Obama himself ducked back inside the White House to spirit away the gift -- whose contents remain a mystery for now.