The United States said Thursday it is closely monitoring the situation on the Korean Peninsula after North Korea fired off a barrage of projectiles into the East Sea in an apparent gesture of defiance following the United Nations' imposition of new sanctions.

"We have seen the reports and will continue to monitor the situation closely. For more details, we refer you to the government of the Republic of Korea," State Department spokesman Ory Abramowicz told Yonhap News Agency in response to a query about the North's launches.

According to South Korea's Defense Ministry, the North fired six short-range projectiles off its east coast Thursday. Sources said the projectiles flew 100 to 150 kilometers before falling into the sea and are believed to be 300 millimeter rockets or short-range missiles.

The launches came just hours after the U.N. Security Council unanimously adopted the harshest-ever sanctions on Pyongyang for carrying out its fourth nuclear test on Jan. 6 and its long-range rocket launch on Feb. 7 in violation of U.N. bans.

Thursday's firings could be a message to the outside world that the communist nation remains unfazed by the new sanctions and will forge ahead with its nuclear and missile programs, analysts said. (Yonhap)