A North Korean missile launch attempt on Sunday has resulted in failure, according to South Korea’s military.

“The North attempted to launch an unidentified missile from near the Sinpo region this morning but it is suspected to have failed,” South Korea’s Office of the Joint Chiefs of Staff said in a statement, according to Reuters.

“The missile blew up almost immediately,” the U.S. Pacific Command said in a press release, adding that “the type of missile is still being assessed.”

Secretary of Defense Jim Mattis said that president was aware of the test launch but was not giving further comments. Vice President Mike Pence, who will kick off a 10-day trip to Asia in Seoul, South Korea on Sunday, was also briefed within one hour of his departure.

Timed one day after the 105th anniversary of the birth of Kim Il Sung, the country’s founder and the grandfather of current Supreme Leader Kim Jong Un, the failed launch represents yet another act that increases tension between North Korea and the U.S.

North Korea’s government held a parade Saturday, showing off two new intercontinental ballistic missiles, a submarine-launched ballistic missile and land-based missile.

President Donald Trump has taken a more aggressive stance against North Korea and has intensified his calls to “solve” problems with the country. The U.S. sent a Navy strike group to the Korean Peninsula earlier this week.

North Korea has stated that it is prepared to respond in turn.

“Our revolutionary strong army is keenly watching every move by enemy elements with our nuclear sight focused on the U.S. invasionary bases not only in South Korea and the Pacific operation theater but also in the U.S. mainland,” state-run newspaper Rodong Sinmun said.

Trump has appealed to China, one of North Korea’s few allies, to play a greater role in thwarting the threat. The president made it clear that he would welcome Beijing’s help but has warned that he’s prepared to act alone.

North Korea is looking for trouble. If China decides to help, that would be great. If not, we will solve the problem without them! U.S.A. — Donald J. Trump (@realDonaldTrump) April 11, 2017

Trump and Chinese President Xi Jinping met last weekend at Mar-A-Lago and discussed a variety of issues, including the North Korean threat. In a phone call on Wednesday, Xi urged the U.S. to resolve the issue “through peaceful means.”

North Korea has ramped up work on its missile program in recent months and has been fine-tuning its intercontinental ballistic missile technology. And the country has already conducted several missile tests this year. Experts project that the program will be sophisticated enough to strike the U.S. by 2026.

Pence, during his visit to Seoul, plans to reinforce security alliances in the region and discuss the North Korean threat, according to Pacific Command.

This is a developing story. Please check back for updates.