WASH­ING­TON – Barack Oba­ma and Don­ald Trump put acer­bic rows and pro­found dif­fer­ences aside in a 90-minute tran­si­tion meet­ing at the White House yes­ter­day, hop­ing to quell fears about the health of the world's pre-em­i­nent democ­ra­cy.

The out­go­ing pres­i­dent and his suc­ces­sor met one-on-one and sat in high-backed chairs be­fore the Oval Of­fice fire­place for what Oba­ma char­ac­terised as an "ex­cel­lent con­ver­sa­tion."

The meet­ing, which came less than 36 hours af­ter Trump's shock elec­tion vic­to­ry over De­mo­c­rat Hillary Clin­ton, had the po­ten­tial to be awk­ward. The two had trad­ed barbs dur­ing the heat­ed bat­tle for the White House.

Trump, who pre­vi­ous­ly called Oba­ma the "most ig­no­rant Pres­i­dent in our his­to­ry," said it was a "great ho­n­our" meet­ing with the US leader, adding that he looked for­ward to re­ceiv­ing the Pres­i­dent's coun­sel.

Oba­ma, who pre­vi­ous­ly said Trump was a whin­er and "unique­ly un­qual­i­fied" to be com­man­der-in-chief, vowed his sup­port. He told Trump his ad­min­is­tra­tion would "do every­thing we can to help you suc­ceed be­cause if you suc­ceed, then the coun­try suc­ceeds."

The two men end­ed the im­prob­a­ble and his­toric White House en­counter with a hand­shake and re­fused to take ques­tions

"Here's a good rule. Don't an­swer ques­tions when they just start yelling," Oba­ma told Trump, re­fer­ring to the press.

White House of­fi­cials said the two men had dis­cussed a range of is­sues, in­clud­ing Oba­ma's meet­ings with lead­ers from Ger­many, Greece and across the Asia-Pa­cif­ic dur­ing for­eign trav­el next week.

On that trip, Oba­ma is like­ly to be in­un­dat­ed with pan­icked ques­tions about Amer­i­ca's role in world af­fairs.

Anger over the Re­pub­li­can prop­er­ty mogul's up­set elec­tion win over Clin­ton spilled out on­to the streets of US cities late Wednes­day, as chant­i­ng pro­test­ers lit bon­fires and snarled traf­fic.

But in the days af­ter Trump's shock elec­tion win, which vir­tu­al­ly no poll had pre­dict­ed, both sides spoke of heal­ing the deep di­vi­sions sown in a bruis­ing two-year cam­paign.

The Re­pub­li­can Par­ty lead­er­ship, too, em­braced their new-found cham­pi­on yes­ter­day.

House Speak­er Paul Ryan, who had dis­tanced him­self from Trump in the fi­nal month of the cam­paign, pledged to "hit the ground run­ning" and work with him on con­ser­v­a­tive leg­is­la­tion.

The two, along with Vice-Pres­i­dent-elect Mike Pence, met on Capi­tol Hill for lunch af­ter Trump's talks with Oba­ma.

On Wednes­day, Trump hud­dled at Trump Tow­er in New York with a group of ad­vis­ers, plan­ning a tran­si­tion strat­e­gy to take over stew­ard­ship of the world's largest econ­o­my.

Team Trump un­veiled a tran­si­tion web­site – www.greata­gain.gov – that high­lights the colos­sal hu­man re­sources chal­lenge fac­ing the in­com­ing ad­min­is­tra­tion un­der the head­line "Help want­ed: 4,000 pres­i­den­tial ap­pointees."

Dur­ing a bit­ter cam­paign that tugged at Amer­i­ca's de­mo­c­ra­t­ic fab­ric, the ty­coon pledged to de­port il­le­gal im­mi­grants, ban Mus­lims from the coun­try and tear up free-trade deals.

Those cam­paign mes­sages were em­braced by a large sec­tion of Amer­i­ca, grown in­creas­ing­ly dis­grun­tled by the scope of so­cial and eco­nom­ic change un­der Oba­ma.

But they were pas­sion­ate­ly re­ject­ed by Clin­ton sup­port­ers.

Thou­sands of pro­test­ers – in New York, Los An­ge­les, Boston, Chica­go, Philadel­phia, Port­land and oth­er cities and school cam­pus­es – ral­lied Wednes­day to ex­press con­tin­ued op­po­si­tion to the in­com­ing leader they ac­cuse of racism, sex­ism and xeno­pho­bia. In Los An­ge­les, a gi­ant Trump head was burned in ef­fi­gy. (AFP)