President Yoon Suk Yeol's approval rating has dropped to 34 percent, marking the lowest level since May, a poll showed Monday.

The opinion poll, conducted by polling agency Realmeter, showed the positive assessment of Yoon's performance decreased by 3.7 percentage points from the previous week, while 62.2 percent of respondents disapproved of his performance, up 2.4 percentage points from the same period.

This marks the first time since the first week of May that his approval rating has fallen below the 35 percent level.

The pollster did not provide a reason for the decline, but major issues during the survey period include the ruling People Power Party's crushing defeat in the by-election for Seoul's Gangseo Ward office.

The approval rating of the People Power Party fell by 4.3 percentage points from the previous week to 32 percent, marking its lowest point since the Yoon administration took office last May.

On the other hand, the approval rating of the main opposition Democratic Party advanced by 2.9 percentage points from the previous week, reaching 50.7 percent, marking the highest level under the current administration, the poll showed.

The poll on the president's performance was conducted on 2,004 adults from Oct. 10-13 and had a margin of error of plus or minus 2.2 percentage points. A separate poll on approval ratings of the political parties was conducted on 1,003 adults from Oct. 12-13 and had a margin of error of plus or minus 3.1 percentage points. (Yonhap)