North Korean leader Kim Jong-un was was handed a letter from new Chinese leader Xi Jinping when a Chinese delegation met the regime's young leader in Pyongyang, the North's official KCNA news agency reported on Friday.

Senior Chinese apparatchik Li Jianguo briefed Kim on the 18th National People's Congress of the Chinese Communist Party, which came to an end on Nov. 14.

"The firm and unwavering policy of the Chinese party and government is to endlessly consolidate and develop the traditional China-[North Korea] relations of friendship and cooperation," Li was quoted as saying.

North Korean leader Kim Jong-un (left) is given a letter from new Chinese leader Xi Jinping by Li Jianguo in Pyongyang on Friday. /[North] Korean Central News Agency

Kim was quoted as saying, "The 18th National People's Congress of the CCP served as a historic event that provided a new milestone to accelerate Chinese-style socialist construction. I expect, and am confident, that China will achieve its strategic goal of socialist construction."

The agency did not reveal what Xi's letter said.

The Chinese delegation returned home on Saturday, a day before North Korea announced another rocket launch attempt later this month that is widely seen as a cover to test long-range missile technology. Beijing issued a mild protest with reference to UN resolutions that ban such tests and urged calm.