The UN Security Council has unanimously backed a new resolution imposing fresh sanctions on North Korea in retaliation for its controversial nuclear programme.
Among the sweeping measures is an export ban aimed at depriving Pyongyang of $1bn (£767m) in annual revenue - around a third of its export earnings.
Kim Jong Un's regime will be banned from selling coal, iron and iron ore, lead and lead ore, fish and seafood.
It will also be prevented from increasing the number of workers it sends overseas - whose earnings are another source of revenue for the regime.
President Trump said the move would have a "very big financial impact" on the reclusive state.
He tweeted: "United Nations Resolution is the single largest economic sanctions package ever on North Korea. Over one billion dollars in cost to N.K."
The resolution will prohibit countries starting new joint ventures with the North and any fresh investment in current joint ventures.
Nine officials and the country's main foreign exchange bank have also been added to the UN sanctions blacklist.
But there will not be the cuts to oil deliveries initially proposed by the US - a move which would have dealt a serious blow to the economy.
The Security Council has already imposed six rounds of sanctions that have failed to halt North Korea's drive to improve its ballistic missile and nuclear weapons capabilities.
US ambassador to the UN Nikki Haley said penalties against the regime have now been taken "to a whole new level" and the Security Council had put the leader "on notice".
She said: "This is the most stringent set of sanctions on any country in a generation."
Meanwhile, UK ambassador to the UN, Matthew Rycroft, warned Kim Jong Un's nuclear ambitions could be "catastrophic for the world".
"North Korea bears full responsibility for the measures we have enacted," he said.
"By acting in flagrant violation of its legal obligations, by going against the will of the Security Council expressed in countless resolutions, North Korea has chosen the path it now finds itself on."
The US has been putting pressure on China, which accounts for 90% of the North's trade, to enforce the sanctions.
The effectiveness of the new measures will be mostly down to whether Bejing cooperates.
Despite eventually backing the resolution, China and Russia had resisted the US clampdown - arguing dialogue with the North was the best way to persuade Pyongyang to halt its military ambitions.
Chinese Foreign Minister Wang Yi said he had urged his North Korean counterpart to abide by UN resolutions and end testing of missiles.