Experts caution North Korea is testing 'creative' weapons that threaten US -- but Trump couldn't care less
North Korea leader Kim Jong-un and President Donald Trump. (Official White House photo.)

President Donald Trump gushed at love letters sent to him from North Korean dictator Kim Jong Un. Trump had claimed that the country was ready and eager to sign a denuclearization treaty, but the event was canceled at the last minute when Trump failed at the negotiation.

Months later, North Korea is now "testing" more weapons, some of which could reach U.S. land and certainly could hit U.S. allies like Japan or South Korea. It's something that Americans should be more concerned about, at least one expert told CNN.

"This is really imaginative or creative thinking of using missiles," said former director of South Korea's National Security Council Choi Kang. He now works with a conservative think tank in Seoul, the Asan Institute for Policy Studies.

Still, Trump isn't fazed by any of the new weapons.

“I have no problem,” Trump told reporters outside the White House in August. “These are short-range missiles.”

If America continues to ignore the tests, however, it could signal that South Korea should go shopping for another ally.

"It seems to me that North Korea has a very, very strong indigenous missile capability and ... (is able) to deploy all the missiles in a very short period time," Choi cautioned.

It's the attitude that is most concerning for Choi and other experts because it shows that North Korea has found a solution for two weapons systems that target completely different altitudes. The Terminal High Altitude Area Defense (THAAD) can target at a range of 50 to 150 kilometers (31 to 93 miles), CNN explained. Where the Patriot system covers 30 kilometers (19 miles) and below.

The altitude would enable North Korea to evade South Korean missile defense systems.

"Kim Jong Un has been, you know, pretty straight with me, I think," Trump told reporters later on in August as the tests continued. "And we're going to see what's going on, see what's happening. He likes testing missiles, but we never restricted short-range missiles, we'll see what happens. Many nations test those missiles."