The term "comrade" was not used for North Korean leader Kim Jong-un in a message sent by Chinese President Xi Jinping to congratulate Kim on his election as chairman of the North's ruling party.

China's state-controlled media on Tuesday reported that Xi sent the message written in Chinese to Kim, but the term was not used to address the North Korean head.

In an English-language article, China's official Xinhua News Agency also reported that Xi "congratulated Kim Jong-un on his election as chairman of the Workers' Party of Korea."

However, North Korea's state media reported that Xi used the term "comrade" to address Kim in the congratulatory message.

In the wake of the 70th anniversary of the founding of the North Korean ruling party, the Chinese president sent a congratulatory message to Kim in October last year.

At that time, Xi described the North Korean leader as a "comrade."

Kim, who took power in late 2011 following the death of his father, consolidated his grip on power as the North's ruling party wrapped up its first congress in 36 years.

The congress reaffirmed North Korea's claim as a nuclear weapons state.

Political ties between North Korea and China remain frayed over the North's defiant pursuit of its nuclear and missile programs.

China backed the latest U.N. sanctions to punish North Korea for conducting its fourth nuclear test in January. (Yonhap)