By Hyunsu Yim, Nicoco Chan, Minwoo Park SEOUL (Reuters) -While South Korean protesters have long employed songs, dances and chants, customised light sticks popular with K-pop fans have emerged as an effective new tool for demonstrators calling for the impeachment of President Yoon Suk Yeol.

Opposition lawmakers failed to impeach President Yoon Suk Yeol over the political crisis he sparked by declaring martial law earlier this week. Tens of thousands of protesters had gathered.

On Saturday, the initial impeachment effort failed after Yoon's People Power Party boycotted the session, preventing quorum to hold the vote. To impeach Yoon, at least 200 of the parliament's 300 lawmakers must vote in support of the move. The ruling party holds 108 seats in the legislative body.