It wasn't immediately clear what type of weapon was tested early Friday, but South Korea's military noted the missiles traveled at hypersonic speeds and flew about 137 miles.
Pyongyang said the new multiple rocket system would cause "inescapable distress" to enemy forces. The test on Wednesday was first thought to be of a short-range ballistic missile.
The latest test of two short-range missiles follows a similar launch last week. It comes as Secretary of State Mike Pompeo said he is "hopeful" talks between Washington and Pyongyang will resume soon.
The test of short-range missiles — one of which may be a new design — is seen as a pressure tactic on Washington as Pyongyang warns against a resumption of U.S.-South Korea military exercises.
Pyongyang accused the U.S. of "unilaterally reneging on its commitments" and said North Korea is "gradually losing our justification to follow through" on its own promises.
The 29-year-old smiled at reporters upon arriving at the airport in Beijing Thursday, telling them he felt "great." But he declined to elaborate on his whereabouts since he was first reported missing.
The two countries are marking the 70th anniversary of their establishment of diplomatic relations. But some experts believe Xi Jinping's trip has another purpose.
The leaders are scheduled to meet on Thursday, according to Chinese and North Korean news agencies. The visit comes after stalled negotiations with President Trump.