'Thought it was going to be a smooth transition!'

US President-elect Donald Trump poured kerosene on a simmering dispute with Barack Obama yesterday, accusing him of derailing a smooth transition with "inflammatory" statements and "roadblocks."

Ever since the November 8 election, Trump and Obama have tried to bury political differences in favor of a united public front that would smooth the transfer of power on January 20.

But the Republican president-in-waiting unceremoniously cast any bonhomie aside in a morning twitter tirade . In a declaration that is unprecedented in its personal condemnation of a soon-to-be predecessor, the 70-year-old tweeted: "Doing my best to disregard the many inflammatory President O statements and roadblocks."

"Thought it was going to be a smooth transition - NOT!"

Tensions between Trump and the current White House have been growing for weeks as Obama has become more outspoken about a vitriol-filled election.

Obama -- who is still the most popular politician in the country -- recently suggested that he may have won a third term were he not constitutionally barred. That seems to have irked the notoriously thin-skinned president-elect.

Trump followed up Wednesday's early tweet with another two taking aim at Obama's policy toward Israel.

"We cannot continue to let Israel be treated with such total disdain and disrespect. They used to have a great friend in the US, but....." he wrote.

"Not anymore. The beginning of the end was the horrible Iran deal, and now this (UN)! Stay strong Israel, January 20th is fast approaching!"