A senior official of South Korea's main intelligence agency has been questioned over allegations that the agency sought to sway public opinion in an attempt to influence last year's presidential election, prosecutors said Friday.

The director of an anti-North Korea psychological warfare team at the National Intelligence Service is suspected of ordering other agents to post a slew of politically sensitive comments on the Internet prior to the Dec. 19 election, according to prosecutors.

The official was questioned on Thursday, they said.

Wrapping up a four-month investigation, the Suseo Police Station announced last week that two other NIS agents, including a female, had allegedly participated in the illegal political activities without an order.

After a police probe failed to uncover the truth about the high-profile scandal, the prosecution immediately launched the team to look into the suspicions that the NIS had extensively and systemically intervened in the presidential election.

"The director responded faithfully to the questions," a prosecutor close to the investigation said, adding that the prosecutors will review whether to summon him one more time for further questioning.

The director, who is currently under a travel ban, previously twice disobeyed the police request to appear for questioning in connection with the scandal. (Yonhap News)