North Korea fired off what appear to have been two short-range ballistic missiles on Friday.
The launches came just hours after the country lashed out over new sanctions.
The Biden administration imposed new sanctions on Wednesday over recent missile launches.
North Korea fired off more missiles Friday morning after warning of a "stronger and certain reaction" in response to sanctions.
Two missiles believed to be short-range ballistic missiles were launched about 11 minutes apart from an area in western North Pyongan province, the Associated Press reported, citing the South Korean military.
The missiles splashed into the sea after flying roughly 267 miles at a maximum altitude of 22 miles.
US Indo-Pacific Command said in a statement on this event that "the missile launch highlights the destabilizing impact of the DPRK's illicit weapons program," adding that "the US commitment to the defense of the Republic of Korea and Japan remains ironclad."
The launches conducted on Friday marked the third launch event that North Korea has carried out this year.
On January 5, North Korea fired off what it called a "hypersonic missile." The weapon, according to expert observers and South Korea, appeared to be a maneuverable re-entry vehicle able to fly at hypersonic speeds - speeds greater than five times the speed of sound.
Then on January 11, North Korea launched what the South Korean military called a "more advanced" missile that hit a top speed of Mach 10.
In response to North Korea's missile activities - which appear to be focused on developing the kind of hypersonic missile capabilities that the US, China, and Russia are all actively pursuing - the Biden administration imposed its first sanctions intended to impede North Korea's weapons development programs Wednesday.
The US sanctioned five North Koreans said to have been involved in acquiring materials for North Korea's prohibited weapons programs. The US also recommended that some sanctioned individuals be blacklisted by the United Nations Security Council.
US Under Secretary of the Treasury for Terrorism and Financial Intelligence Brian Nelson said that recent launches are "further evidence that it continues to advance prohibited programs despite the international community's calls for diplomacy and denuclearization."
As the US imposed sanctions, US State Department spokesman Ned Price emphasized that any progress toward changing the current situation with North Korea will need to come from dialogue.
North Korea's foreign ministry issued a sharply worded statement Friday arguing that its missile activities are "part of its efforts for modernizing its national defense capability" in accordance with its "right to self-defense."
"The US is intentionally escalating the situation even with the activation of independent sanctions, not content with referring the DPRK's just activity to the UN Security Council," the foreign ministry stated. "If the US adopts such a confrontational stance, the DPRK will be forced to take stronger and certain reaction to it."
While North Korea did not clarify in its statement what that reaction would be, the statement was followed just a few hours later by North Korea's latest missile launches.