President Trump took aim at China and Iran while chairing a U.N. Security Council meeting on nonproliferation on Wednesday -- accusing China of meddling in the U.S. midterms, and promising sanctions “tougher than ever before” on Iran.

Trump spoke first and, within minutes, trained his sights on Syria, Iran and Russia. He claimed that the “Syrian regime’s butchery” was enabled by Iran and Russia. He then accused the Iranian regimes of exporting "violence, terror and turmoil."

"It illicitly procures sensitive items to advance its ballistic missile program and proliferates these missiles all across the Middle East," he said. "The regime is the world's leading sponsor of terror, and fuels conflict across the region and far beyond."

While he thanked the trinity for “substantially slowing down their attack on Idlib province,” he warned: “Get the terrorists, but I hope the restraint continues. The world is watching."

TRUMP TRADES FIRE WITH IRANIAN LEADER AT UN GENERAL ASSEMBLY

At the meeting, he defended his administration’s decision to pull out of the 2015 Iran nuclear deal, and blasted what he called a “horrible, one-sided deal [that] allowed Iran to continue its path toward a [nuclear] bomb and gave the regime a cash lifeline when they needed it the most.”

“They were in big big trouble,” he said. “They needed cash, we gave it to them.”

The Trump administration re-imposed a host of economic sanctions on Iran in August, and plans to impose sanctions on Iran’s crude oil exports in November.

Trump said that after that, the U.S. "will pursue additional sanctions, tougher than ever before, to counter the entire range of Iran's malign conduct."

"Any individual or entity who fails to comply with these sanctions will face severe consequences," he warned.

Trump then used the meeting to accuse China of meddling in the November midterms, saying it was pushing back against Trump's tariffs that he has placed on goods from China entering the U.S.

“Regrettably we found that China has been attempting to interfere in our upcoming 2018 election coming up in November against my administration,” he said.

“They do not want me or us to win because I am the first president ever to challenge China on trade and we are winning on trade. We are winning on every level.”

While Trump did not give any specifics about alleged interference, he seemed to referring back to a point he made in a tweet earlier this month when he accused China of “actively trying to impact and change our election by attacking our farmers, ranchers and industrial workers because of their loyalty to me.”

Chinese Foreign Minister Wang Yi responded to Trump's comments at the meeting, saying that China follows a principle of non-interference in other countries domestic affairs.

"We did not and will not interfere in any country's domestic affairs, we refuse to accept any unwarranted accusations against China and we call upon other countries to also observe the purposes of the U.N. Charter and not interfere in other countries' internal affairs," he said.

Trumps’ remarks come a day after a fiery speech to the U.N. General Assembly, where he also had harsh words for Iran.

"We cannot allow the world's leading sponsor of terrorism to possess the planet's most dangerous weapons," he said. "We cannot allow a regime that chants 'Death to America' and that threatens Israel with annihilation to possess the means to deliver a nuclear warhead to any city on Earth.

"Just can't do it."

In turn, Iranian President Hassan Rouhani took aim at Trump, and even his decision to call the Security Council meeting.

"It is unfortunate that we are witnessing rulers in the world who think they can secure their interests better -- or at least in the short-term ride public sentiments and gain popular support -- through the fomenting of extremist nationalism and racism, and though xenophobic tendencies resembling a Nazi disposition, as well as through the trampling of global rules and undermining international institutions; even through preposterous and abnormal acts such as convening a high-level meeting of the Security Council," he said.

Fox News' Ben Evansky contributed to this report.