“As one citizen and as ​the president responsible for the government, I express deep regret,” Lee ​said in an X post.

Last week’s local elections were hit by ⁠a ballot shortage that prevented some eligible voters from casting ballots.

The head ​of the National Election Commission (NEC), the independent body that oversaw the vote, resigned ​after the incident.

Thousands have since protested outside a ballot-counting site in Seoul, demanding a re-run.

Opposition calls for joint audit

Lee said the incident was “difficult to comprehend” and that the NEC’s response and explanations ​were insufficient.

He said he had asked parliament to conduct a fact-finding probe, ​establish measures to prevent a repeat and discuss reform plans for the commission.

Jang Dong-hyeok, leader ‌of ⁠the opposition conservative People Power Party, told a press conference on Sunday that he had visited the protests and called for a joint audit with Lee’s Democratic Party.

He said ballot shortages were especially severe in areas that lean conservative, but ​stopped short of calling ​for a re-run, ⁠saying he would “obey whatever the people’s commands say”.

The Democratic Party swept major local races, but the opposition retained Seoul’s mayoralty, with incumbent ​Oh Se-hoon winning another term.

The NEC said 50 of 14,300 ​polling stations ⁠ran out of ballots, while voting was temporarily suspended at 22 due to delays in supplies.

In Seoul, delays were reported at 12 locations in Songpa district, ⁠a conservative ​stronghold.

At one Songpa polling station, an angry ​crowd blocked officials from moving ballot boxes to be counted after voting ended.