"We are... aware of military activity last weekend by the DPRK [North Korea] that is not sanctioned by the UN Security Council resolutions restricting the ballistic missile program," the official said on Tuesday evening.
The official characterized the launches as "normal military activity" by North Korea and added that they fell short of the "provocative actions" category.
Earlier in the day, US Defense Department spokesperson John Kirby declined to comment on media reports that North Korea had conducted nuclear tests over the weekend.
"I have nothing for that right now," Kirby said during press briefing.
On Tuesday, US media reported that North Korea had launched several short-range missiles over the weekend. The reason for North Korea doing so may have been joint US-South Korea military exercises that Pyongyang had repeatedly complained about, according to reports said citing sources familiar with the issue.