President Yoon Suk-yeol speaks to reporters as he arrives at the presidential office in Seoul on Sept. 16. Yonhap

President Yoon Suk-yeol said Friday he instructed the justice ministry to come up with improvements to the anti-stalking law following the shocking murder of a subway worker by a colleague inside a subway station restroom.

The 20-something victim was killed inside a ladies' restroom at Sindang Station on Line 2 on Wednesday after being stalked by the suspect for years.

"The news is causing great shock to the people," Yoon said as he arrived for work. "The anti-stalking law was enacted last year, but many said it wasn't enough to protect victims. I told the justice ministry before leaving on my trip to remedy the system and fully ensure that victims are protected so as to leave no room for such crimes."

Yoon is set to depart Sunday on a three-nation tour of London, New York and Canada.