North Korean leader Kim Jong-un visits the Friendship Tower in Pyongyang, symbolizing the friendly ties between his country and China, July 26, one day ahead of the signing of the armistice that ended the 1950-53 Korean War, in this photo carried by the North's official Korean Central News Agency. Yonhap

North Korean leader Kim Jong-un has said "kindred" relations with China will be "firmly" carried forward as he visited a monument symbolizing bilateral ties, state media reported Saturday, amid suspected signs of strain between the traditionally friendly countries.

On Friday, Kim visited the Friendship Tower in Pyongyang, which was erected to commemorate China's participation in the 1950-53 Korean War, and paid tribute to fallen Chinese soldiers during the war, a day ahead of the 71st anniversary of the armistice that ended the conflict, according to the Korean Central News Agency (KCNA).

"He expressed belief that the DPRK-China friendship established as the ties of kindred would be firmly carried forward and developed along with the immortal spirit of the martyrs," the KCNA said in an English-language dispatch.

DPRK stands for the North's official name, the Democratic People's Republic of Korea.

The Korean War, which started with an invasion by North Korea, ended in a truce, not a peace treaty, on July 27, 1953. North Korea celebrates the armistice signing date as Victory Day, claiming it won what it calls a liberation war against U.S.-led aggression.

Kim's visit came as the North has appeared to be aligning closer to Russia and away from China, with the North's leader and Russian President Vladimir Putin signing a "comprehensive strategic partnership" agreement during their summit in Pyongyang last month.

North Korean leader Kim Jong-un assists a Korean War veteran, during his visit to the Fatherland Liberation War Martyrs Cemetery in Pyongyang, July 26, one day before the signing of the armistice that ended the 1950-53 Korean War, in this photo carried by the North's official Korean Central News Agency. Yonhap

Earlier this month, the Rodong Sinmun, the newspaper of the North's ruling party, did not carry any articles on the anniversary of the signing of the friendship treaty between North Korea and China as it had done so on the anniversary date in the past.

Separately, Kim also visited a cemetery in Pyongyang, Friday, for North Korean soldiers who died during the Korean War, along with elderly war veterans, according to the KCNA.

"It is the sacred mission and duty of our generation to reliably defend our ideology and social system, safeguarded by the victorious wartime generation at the cost of blood, and build a people's paradise," Kim was saying in another English-language KCNA report.

Kim has visited the Fatherland Liberation War Martyrs Cemetery every year around the time of the anniversary of the armistice signing.

The North's leader also visited the Revolutionary Martyrs Cemetery on Mount Taesong later that day, where forces who fought against Japan's 1910-45 rule of the Korean Peninsula under his late grandfather Kim Il-sung remain buried.

It marked the first time Kim visited the cemetery on the occasion of the armistice signing anniversary, in an apparent effort to emphasize their importance. (Yonhap)