North Korea has confirmed Kim Jong-un's visit to Russia in May, which would be the first foreign trip of the supreme leader since coming to power three years ago.

The heads of state of North Korea and 19 other countries have already confirmed their participation in the commemoration of the 70th anniversary in May of the World War II victory over Nazi Germany, according to South Korea's Yonhap news agency which quoted a Russian government spokesperson.

The spokesperson, however, did not specifically mention Kim's name, leaving room for ambiguity as North Korea also has an honorary head of state in the form of Presidium of the Supreme Assembly President Kim Yong-nam.

But it is believed that it will be supreme leader Kim who will attend the commemoration in Moscow, since Russian President Vladimir Putin had personally sent him an invitation last month.

Kim's trip is expected to be a significant one as he has never met with other heads of state since coming to power in December 2011, following the death of his father Kim Jong-il.

Analysts view the possible visit to Moscow as another sign of growing closeness between North Korea and Russia, which in the last few months have broadened their ties with several agreements for joint initiatives, including an ambitious rail project.

Choe Ryong-hae, considered the “number three” in the North Korean regime, met with Putin in November in Russia, when both parties underlined the need to increase bilateral cooperation.

Analysts have also pointed out that Kim's visit to Moscow could, however, annoy China which is North Korea's historic ally and main economic benefactor.

In contrast to the closeness with Russia, relations between North Korea and China have dampened since Pyongyang conducted its third nuclear test in the beginning of 2013.