A small truck driven by a Seoul man smashed into the Japanese Embassy in central Seoul early Monday morning, but no casualties were reported, police said.

The man detained by police on the scene insisted that he attacked the Japanese embassy in a show of protest against a right-wing Japanese activist's nationalistic insult last month over Korean women forced into sexual slavery by the Japanese military during World War II.

The 61-year-old truck driver surnamed Kim rammed his truck into the embassy's main gate at 4:55 a.m., but policemen on guard immediately restrained him, according to police.

No damage was reported, though the main gate was pushed back by one meter due to the attack.

"I tried to protest against the Japanese man's setting up of the post at the girl statue that represents comfort women," Kim was quoted by police as saying.

Public anger flared up last month after the 47-year-old Japanese man set up the provocative wooden post beside the bronze statue of a young girl in front of the Japanese embassy.

The slim white post tied to the statue read "Dokdo is Japanese territory," a claim in line with those by Japan's extreme rightists.

The bronze statue of a young girl, which was set up in December by former sex slaves and their supporters, symbolizes Korean wartime sex slaves.

Nobuyuki Suzuk, the far-right activist, later posted a video clip on his blog showing him setting up the post and calling the war crime victims prostitutes.

A group of 10 local women who were forced into the sexual slavery during the wartime as comfort women filed a defamation suit with a Seoul prosecutors' office against the Japanese man earlier in the month. (Yonhap News)