"The North Korean regime is causing tremendous problems and is something that has to be dealt with, and probably dealt with rapidly," President Trump told reporters in the White House Rose Garden after holding his first talks with PM Modi.
President Trump also thanked India for "joining us in applying new sanctions against the North Korean regime."
The US president has made halting Pyongyang's weapons program a top foreign policy priority.
Washington has 28,000 troops deployed in South Korea and a naval armada in the region.
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