North Korean leader Kim Jong-un visited a subway station in Pyongyang for a test operation of a newly manufactured subway train, the North's state media said Friday.

Aboard the subway train built with the North's indigenous technology, Kim expressed satisfaction about its performance, according to the Korean Central News Agency.

In the public activity on Thursday, he shuttled from Kaeson Station in the capital to several stations aboard the train to learn about its trial operation in detail, the KCNA said.

Han Kwang-sang, a party official dealing with finance and accounting, was among Kim's entourage, which also included Pak Pong-ju, premier of the Cabinet, it said.

Han, 58, who came back to the public eye for the first time since March, was reportedly under investigation due to corruption allegations.

South Korea's spy agency earlier said that the North Korean leader has tightened his grip on his power base in a brutal way, including the execution of the North's former defense chief Hyon Yong-chol and about 70 senior officials. (Yonhap)