North Korea showed off what appeared to be at least one new long-range missile at a military parade Saturday, as tensions simmer over the possibility of a military confrontation between the U.S. and North Korea.

The weaponry on show, which appeared to include a newly-modified intercontinental ballistic missile and two types of large launchers with never-before-seen missile canisters, is likely to trigger fresh concerns about the speed with which Pyongyang’s missile program has advanced in recent years.

A spokesman for South Korea’s Ministry of National Defense declined to comment on the possible new military hardware, saying more time was needed to analyze the missiles.

But an expert on North Korean weapons said the new hardware appeared to be far more advanced than expected.