A senior Seoul official said Friday that North Korea appears to be operating a hydroelectric power plant near a shuttered inter-Korean industrial complex amid speculation that Pyongyang is unilaterally resuming work at the factory park.

North Korea last week indicated that it restarted the operation of the Kaesong Industrial Complex in the face of tightening economic sanctions. Seoul shut down the joint production zone in February 2016 in response to Pyongyang's nuclear and missile tests.

Unification Minister Cho Myoung-gyon told lawmakers that there are no specific signs it's been reopened, though some bus movement and lit street lamps have been spotted since March or April.

"It has been recently found that North Korea activated a small hydroelectric station," Cho said when asked whether electricity has been supplied to the industrial park during a parliamentary audit session.

North Korea constructed a new hydroelectric power plant near Ryesong River in the country's southwestern province early this year. 

Some experts said that the North can operate sewing machines at the zone with self-powered generators.

The minister said that Seoul is looking into all possibilities as there is not enough evidence to determine whether electricity is supplied by self-powered generators or the power station.

Seoul's Unification Ministry said that North Korea should not resume operations at the complex without permission as the factories and machinery belong to South Korean firms.

It said that if North Korea resumes operations, it would be violating inter-Korean agreements banning the random naturalization of Seoul firms' assets. It could also breach the latest UN

sanctions barring the North's textile exports if the country seeks outbound shipments.

The factory zone, launched in 2004, had accommodated 124 South Korean firms which employed more than 54,000 North Korean workers to produce labor-intensive goods such as clothes and utensils.

Touching on Seoul's plan on US$8 million aid to North Korea, Cho said that the government plans to implement it next year.

The ministry last month approved the plan to provide humanitarian assistance to North Korea through UN agencies, but its timing for actual supply will be decided after taking various factors into consideration including inter-Korean ties.

The move has sparked a row over whether it is proper for Seoul to offer aid to the North when the UN Security Council has stepped up pressure and sanctions on Pyongyang over its nuclear and missile programs.

"The government thinks that the issue of humanitarian aid should be handled separately from the political situation," Cho said. (Yonhap)