The North's leader has strengthened his power since late 2011 when he took office following the sudden death of his father Kim Jong-il.

Last year's party congress, the first one in more than 30 years, was a venue for Kim to reaffirm his unfettered rule.

The anniversary came as North Korea is under a set of US sanctions for its nuclear and missile tests. Pyongyang carried out two nuclear tests last year alone following those in 2006, 2009 and 2013.

North Korea has claimed that its development of nuclear weapons is a deterrent against what it calls Washington's hostile policy towards it.

"At a time when we are going eyeball to eyeball with the US, the current grave situation on the peninsula calls for ceaselessly marching toward implementing tasks unveiled at the party congress," said the Rodong Sinmun, the country's main newspaper.

The paper also said that international sanctions will not have any impact on North Korea, as time is on its side.

"(The US administration) should first have correct understanding about us. We cherish nuclear deterrents and will not give up them whatever people say," it added.

Kim pledged to "permanently" pursue his policy of developing nuclear weapons in tandem with economic growth at the party congress. (Yonhap)