By Yi Whan-woo

North Korea tested a new submarine-launched ballistic missile (SLBM) on March 16, two weeks after the U.N. Security Council (UNSC) imposed its latest sanctions in response to Pyongyang's nuclear and missile tests in January and February, respectively, according to an online U.S. newspaper.

Citing defense officials, the Washington Free Beacon reported Tuesday that a "pop-up" or "ejection test" of a KN-11 missile was carried out.

It said last week's test took place from a canister at the Sinpo shipyard on North Korea's east coast. The site is where a KN-11 missile is under development along with the new Sinpo-class submarine that can carry ballistic missiles.

Both the U.S. and South Korean governments refused to verify the report.

"We're not going to comment on matters of intelligence," U.S Department of Defense spokesman Cmdr. Bill Urban was quoted as saying by the Beacon.

"It's a matter of intelligence and we can't confirm whether the report is true or not," Ministry of Defense spokesman Moon Sang-Gyun said, Wednesday.

If confirmed, the test will be in violation the UNSC's Resolution 2270 approved on March 2.

This imposed the toughest U.N. sanctions on the Kim Jong-un regime for defying previous rounds of U.N. resolutions.

The latest SLBM test comes after the reclusive state test-fired a KN-11 missile on Dec. 21 from a submerged vessel in waters near Sinpo. Pyongyang also failed in an underwater release test of a KN-11 missile on Nov. 28.

An SLBM equipped submarine would make it more difficult for South Korea and the U.S. military to detect a missile attacks in advance.

Since March 2, North Korea has carried out a series of both short- and mid-range missile tests, in an apparent show of anger over the UNSC's punitive measures.

Kim also hinted at carrying out another nuclear test and long-range rocket launches.

The Seoul government said Monday that Pyongyang was capable of conducting its fifth nuclear test "at any time."