A man wearing Captain America's iconic costume shows up at the National Human Rights Commission of Korea's building on Feb. 10. Yonhap

The Chinese Embassy in Seoul expressed regret and concerns Saturday over an attempt by a suspected supporter of now-impeached Korean President Yoon Suk Yeol to trespass into its building the previous day.

"We are concerned and regret this case happened," the embassy told Yonhap News Agency, adding it has shared this view with the South Korean government.

The remarks came a day after police arrested a 40-something man who tried to rush through the gate of the Chinese Embassy in central Seoul without permission.

The man, surnamed Ahn, was wearing Captain America's most iconic costume at the time and reportedly made the attempt after saying he would launch a "terror attack" on the embassy.

Shortly after the arrest, Ahn wrote on his social media account, he intended to deliver "anti-China sentiment" to the embassy.

The embassy said Korean police are investigating the case and will await the results.

Earlier this week, Ahn also appeared at the state human rights watchdog's headquarters in Seoul and caused a disturbance.

The National Human Rights Commission of Korea (NHRCK) adopted a controversial recommendation Monday to guarantee Yoon's right to defense during his ongoing impeachment trial at the Constitutional Court. (Yonhap)