Former President Barack Obama took the stage in Johannesburg, South Africa, on Tuesday to celebrate Nelson Mandela’s 100th birthday. It was his biggest public speech since leaving office in 2017 — and he certainly had some things to say.

Standing in front of a crowd of about 15,000 people, Obama delivered a stark warning about the rise of “the politics of fear” and the ascendancy of far-right parties whose political platforms “are based not just on platforms of protectionism and closed borders, but also on barely hidden racial nationalism.”

“That kind of politics is now on the move,” Obama said. “It’s on the move at a pace that would have seemed unimaginable just a few years ago. I’m not being alarmist; I’m simply stating the facts. Look around.”

Obama also issued a thinly veiled rebuke of President Donald Trump’s tendency to lie continually and the political climate that led to Trump’s victory in the first place. Though he never explicitly mentioned Trump by name, Obama lamented the “denial of facts” that has come to represent today’s political discourse.

“Unfortunately, too much of politics today seems to reject the very concept of objective truth. People just make stuff up,” Obama said. “We see the utter loss of shame among political leaders where they’re caught in a lie and they just double down and lie some more.”

“The denial of facts runs counter to democracy,” he added.

The nearly 90-minute address was highly anticipated after yesterday’s controversial Helsinki summit where Trump essentially sided with Russian President Vladimir Putin over US intelligence agencies on the issue of Russian interference in the 2016 election. Politicians from both sides of the aisle are calling Trump’s behavior “disgraceful” and “shameful.”

It’s unclear how (or if) Trump will react to Obama’s speech. But getting a rise out of the president didn’t seem to be on Obama’s list of intentions.

Rather, Obama ended on a note of encouragement for the young people listening in the audience and worldwide. Bolstering them as future leaders, Obama advised younger generations to “keep believing, keep marching, keep building, [and] keep raising your voice.”