TEHRAN (Press Shia) – US President Donald Trump ramped up his tough rhetoric against North Korea when he arrived in Japan on Sunday, saying that the United States and its allies are prepared to defend freedom and that "no dictator" should underestimate US resolve.

Trump kicked off a 12-day Asian trip and is looking to present a united front with Japan against North Korea through meetings with Japan Prime Minister Shinzo Abe amid heightened tensions over Pyongyang's nuclear and missile tests, CNBC reported.

He told reporters on Air Force One en route to Asia that North Korea would figure prominently in discussions during the trip.

"No dictator, no regime, no nation should ever underestimate American resolve," Trump told hundreds of cheering US and Japanese troops in camouflage uniforms gathered at Yokota Air Base, just west of Tokyo, soon after he arrived.

"We will never yield, never waver and never falter in defense of our freedom," Trump said.

He told reporters earlier on Air Force One that a decision would be made soon on whether to add reclusive North Korea to a list of state sponsors of terrorism.

Trump said his administration planned to take a different approach after years of what he termed "total weakness."

"We want to get it solved. It's a big problem for our country and the world, and we want to get it solved."

Trump also said he planned to meet Russian President Vladimir Putin during his trip, the longest Asian tour by any US leader since George H.W. Bush in 1992.

"I think it's expected that we will meet," he said. "We want Putin's help on North Korea."

Trump wants a united front with the leaders of Japan and South Korea against North Korea before he visits Beijing to make the case to Chinese President Xi Jinping that he should do more to rein in Pyongyang.

A centerpiece of the trip will be a visit to the Asia Pacific Economic Cooperation summit in Danang, Vietnam, where he will deliver a speech in support of a free and open Indo-Pacific region, which is seen as offering a bulwark in response to expansionist Chinese policies.

The US president also singled out trade, which he said had been "badly handled" in the region for years.

"One of the things we're going to be very focused on is trade because trade has not been done well for 25 years by the United States with this part of the world, with any part of the world," he said on Air Force One.

"We're going to be discussing reciprocal trade. Fair, free but reciprocal," Trump said.