US President Barack Obama on Saturday took aim at Democrats and Republicans alike in his final appearance headlining the star-studded White House correspondents' dinner, but saved his sharpest barbs for Republican presidential front-runner Donald Trump.

"The Republican establishment is incredulous that he's their most likely nominee," Obama told attendees at the black-tie event, which brought together journalists and media moguls with Hollywood stars and power brokers from Capitol Hill and beyond.

"They say Donald lacks the foreign policy experience to be president. But in fairness he has spent years meeting with leaders from around the world: Miss Sweden, Miss Argentina, Miss Azerbaijan," the president said to howls of laughter, referring to contestants on the Miss Universe pageant that Trump formerly co-owned.

Obama made fun of the angst many in the Republican establishment have expressed at the prospect that Trump or Tea Party candidate Ted Cruz could win the party's nomination to run in the Nov. 8 presidential election.

"Guests were asked to check whether they wanted steak or fish, but instead a whole bunch of you wrote in Paul Ryan," Obama said, referring to the top Republican in the House of Representatives, who many have hoped could be lured into running for president.

"That's not an option people," Obama said, displaying comedic chops perfected through seven previous appearances at the annual dinner. "You may not like steak or fish, but that's your choice."

In his remarks, Obama looked back on his presidency and jokingly predicted the country may be nearing its doom.

"The end of the republic has never looked better," the tuxedo-clad president said looking out at the well-groomed crowd as he blasted Republican Party Chairman Reince Priebus.

"Congratulations on all your success," Obama told Priebus, while wearing a sarcastic grin. "The Republican party, the nomination process - it's all going great."

Larry Wilmore, the host of a show on cable outlet Comedy Central, took his own shots at Trump when he took the podium after Obama, joking that next year the dinner will be called: "Donald Trump presents a luxurious evening paid for by Mexico."

Trump has famously promised to build a wall between the United States and Mexico to prevent illegal immigration, and he has said he would force Mexico to pay for it.

With a bit of nostalgia, Obama reflected on his more than seven years in office, saying he had been a young man of idealism and vigor before he became president.

"Eight years ago I said it was time to change the tone of our politics," Obama said. "In hindsight, I clearly should have been more specific." – Reuters