WASHINGTON

President Donald Trump said Tuesday that the US and Canada are "working closely" on a new "Golden Dome" missile defense project.

"One thing where we are working very closely is the Golden Dome. That's the protective mechanism. And you see how that works. It's unbelievable," Trump said in the Oval Office as he hosted Canadian Premier Mark Carney.

"We'll be working together on a Golden Dome for the two countries, and it's something that I think is going to be very important, especially when you look at the world, you look at what's happening. We want to have that protection. It's really amazing. The technology is unbelievable," Trump added.

The Golden Dome is the US' proposed multi-layer missile defense system that Trump has proposed. He said in May that he selected the "architecture" for his long-promised program, which he estimated would cost $175 billion to develop over the next three years.