A South Korean man arrested in connection with an explosion at Yasukuni Shrine in Tokyo is believed to have tried to smuggle gunpowder and a timer into Japan when he returned earlier this week, investigative sources said Friday.

Chon Chang-han was arrested Wednesday on a charge of entering the premises of the war-related shrine with unlawful intent, but police now believe the 27-year-old, who is suspected of creating an explosion in a men's restroom there on Nov. 23, was planning another blast, the sources said.

The Shinto facility served a spiritual rallying point during the war and is viewed as a symbol of Japan's past militarism in Asia.