North Korea attempted to launch a missile from its east coast, but it failed, according to the South Korean and US militaries.

“US Pacific Command detected and tracked what we assess was a North Korean missile launch at 11:21am Hawaiian time April 15,” read a statement by the US military. “The missile blew up almost immediately. The type of missile is still being assessed.”

The attempted missile launch comes a day after North Korea paraded intercontinental ballistic missiles in front of the world and its adversaries, including the US, heightened their defenses against a strike. US vice president Mike Pence was also due to arrive in South Korea on Sunday for meetings with the government there.

“North Korea attempted to test an unidentified type of missile from Sinpo area in the South Hamkyong Province this morning, but we suspect the launch has failed,” read a statement by South Korea.

It wasn’t immediately clear if North Korea had attempted to test an intercontinental ballistic missile, which could travel over the Pacific Ocean and reach the United States. The nation’s leader, Kim Jung Un, had recently said his military was close to conducting such a test. Donald Trump, the US president, warned that he was prepared to act if North Korea became more aggressive, though his public statements have been confusing and contradictory.

The attempted missile launch heightens what was already one of the tensest times on the Korean peninsula since North Korea began working to build nuclear weapons and intercontinental missiles.