Former soccer player Lee Chun-soo, left, watches a volleyball game with ex-Land Minister Won Hee-ryong on Wednesday. (Yonhap)

The police on Friday launched a probe into the alleged assault on former soccer player Lee Chun-soo while he was participating in former Land Minister and ruling party candidate Won Hee-ryong’s street campaign ahead of the April 10 general election.

The Incheon Gyeyang Police Station received a report from Won’s office at 10 p.m. on Thursday claiming that Lee, who recently endorsed the former land minister for the upcoming election, was “physically assaulted.”

Lee was attacked as he was helping Won greet citizens commuting to work in the morning near Gyeyang Station, a subway hub in Incheon, according to the ruling People Power Party candidate’s Facebook post uploaded on Thursday.

The male assailant, whose identity is unknown at the moment, attacked Lee after approaching to shake his hand, according to the post. He first grabbed Lee’s hand before kicking the soccer player’s thigh with his knee. The assailant then made further attempts to assault Lee, but was stopped by the “people around him,” Won’s post explained.

Police officers said they have secured the surveillance footage of the incident and are currently tracking down the suspect. Meanwhile, prosecutors are looking into the case and are reviewing whether to indict the suspect for breaching the Public Official Election Act.

Lee was also threatened in person, the same day, by a separate man holding a drill, according to the same Facebook post by Won. The man claimed that he “knew where Lee’s family lived.”

Won denounced such threats saying that “it’s an evident crime.” He pledged to prevent such assaults and threats from happening again in the future.

Thursday’s incident comes as the nation is on high alert over recent and possible assaults against politicians ahead of the general election.

On Jan. 2, main opposition Democratic Party of Korea Chair Lee Jae-myung was stabbed by a male assailant posing as his supporter during his visit to an airport construction site in Busan. Lee underwent surgery for a laceration to a major vein in his neck and returned to work later in the same month.

The incident was closely followed by an attack against People Power Party Rep. Bae Hyun-jin who was repeatedly struck in the head with a rock by a teenager on Jan. 25. Bae also suffered a wound on her scalp and was hospitalized.

President Yoon Suk Yeol and lawmakers voiced concerns with both attacks, while calling such assaults against politicians "acts of terrorism."