(CNN)US President Donald Trump addressed the South Korean parliament in Seoul Wednesday, with a fiery speech that was full of criticism of the country's northern neighbor and particularly its leader Kim Jong Un.
5 key moments from Trump's South Korea speech
One of the key points of Trump's speech was the contrast between North and South Korea.
"The very existence of a thriving South Korean republic threatens the very survival of the North Korean dictatorship," he said. "This city and this assembly are living proof that a free and independent Korea not only can, but does stand strong, sovereign and proud among the nations of the world."
"In this republic, the people have done what no dictator ever could," Trump added. "You took -- with the help of the United States -- responsibility for yourself and ownership of your future. You had a dream, a Korean dream, and you built that dream into a great reality.
However, while South Korea today outstrips its northern neighbor on practically every measure, in the decades after the Korean War, it was Pyongyang, not Seoul, which could boast a greater quality of life and economic success.
Both countries were also ruled by dictatorial strongmen until the late 1980s, when South Korea finally transitioned to a fully civilian, democratic government. Since then, the country's fortunes have far surpassed North Korea's.
Echoing remarks he made alongside South Korean President Moon Jae-in Tuesday, Trump warned North Korea "do not try us."
"History is filled with discarded regimes that have foolishly tested America's resolve," he said. "Anyone who doubts the strength or determination of the United States should look to our past and you will doubt it no longer. We will not permit America or our allies to be blackmailed or attacked."
On Tuesday, Trump highlighted the presence of three US aircraft carriers in the region, along with submarine and warship escorts.
"If you want peace," Trump told South Korean lawmakers, "you must stand strong at all times. The world cannot tolerate the menace of a rogue regime that threatens with nuclear devastation."
At several points in his speech, Trump addressed the North Korean leader Kim Jong Un directly.
"I have also come here, to this peninsula, to deliver a message directly to the leader of the North Korean dictatorship," Trump said. "Every step you take down this dark path increases the peril you face."
"North Korea is not the paradise your grandfather envisioned," he added. "It is a hell that no person deserves."
Later, Trump described North Korea as a "country ruled by a cult."
CNN correspondent Will Ripley, who is currently in Pyongyang, said this type of language is likely to be "more infuriating to the North Koreans than the fiery rhetoric (Trump has) used before" as the US leader "directly criticized their ideology and authoritarian system."
Though Trump had previously indicated he would consider future negotiations with Kim, a point Moon was keen to emphasize Tuesday, his speech was less conciliatory.
"In 2009, the United States gave negotiations yet another chance and offered North Korea the open hand of engagement," he said. "The regime responded by sinking a South Korean navy ship (in 2010), killing 46 Korean sailors."
As the North Korean issue has consumed the first year of his presidency, Trump has been adamant that Beijing must do more to rein in its longtime ally.
Echoing comments made earlier this week, Trump called on "every nation, including China and Russia, to fully implement UN Security Council resolutions, downgrade diplomatic relations with the regime, and sever all ties of trade and technology."
He heads to the Chinese capital later Wednesday, and, amid a litany of alleged North Korean human rights abuses, he gave an example of why Beijing should be wary of its neighbor.
"North Korean women are forced to abort babies that are considered ethnically inferior. And if these babies are born, the newborns are murdered," Trump said. "One woman's baby born to a Chinese father was taken away in a bucket. The guard said it did not deserve to live because it was impure."
Appealing to China's morality is a different tack for Trump, and may be a preview of how he plans to approach the North Korea issue with President Xi Jinping.
One of the largest applause lines in Trump's speech was nothing to do with politics, but came when he poured praise on South Korea's golfing prowess.
"The women's US Open was held this year at Trump National Golf Club in Bedminster, New Jersey, and it just happened to be won by a great Korean golfer, Sung Hyun Park, and eight of the top 10 players were from Korea," Trump said.
"And the top four golfers -- one, two, three, four -- the top four were from Korea. Congratulations."