North Korean leader Kim Jong Un on Tuesday hailed the country's recent submarine-launched ballistic missile (SLBM), despite international censure, reports said, citing official news agency KCNA. The missile test, conducted earlier this month, has been shrouded by controversies due to increasing concerns about the region's security.

KCNA said, according to Agence France-Presse, that Kim hosted a gathering of scientists and technicians, who conducted and contributed to the test and congratulated them. He praised them for an "eye-opening miracle" and a "historical event" that created a powerful strategic weapon.

“The acquisition of the SLBM firing technique is another historical event which fully displayed the dignity and might of Kim Il Sung’s (Kim Jong Un’s grandfather) and Kim Jong Il’s (Kim Jong Un’s father) Korea over the world,” Kim said, according to Yonhap, which cited the KCNA.

The threat from North Korea’s nuclear capabilities will reportedly increase manifold with an SLBM as the country will be able to deploy the missile much further than the Korean peninsula.

However, experts have questioned the authenticity of the photographs from the recent tests, saying the missiles were fired from a submerged platform, and not a submarine. Some have also raised suspicions that the photographs were digitally manipulated.

North Korea currently faces sanctions from the United Nations and is banned from developing or using ballistic missile technology.

South Korea said Tuesday that it has asked the U.N. to investigate if the North’s move violated sanctions. "We've sent a letter to the UN Sanctions Committee," Noh Kwang Il, spokesman for the South Korean foreign ministry, told AFP.

After the test-fire, North Korea had also threatened "targeted strikes" against South Korean navy, accusing it of violating territorial waters near the western sea border. U.S. Defense Secretary Ashton Carter, had reportedly said at the time, “It’s a reminder of how dangerous things are on the Korean peninsula and how a highly ready force in support of a very strong ally … is necessary to keep the peace out there.”