Rival parties have launched campaign activities for the April 15 general elections as the official campaign period kicked off Thursday. 

Former Prime Minister and co-chair of the ruling Democratic Party's election committee Lee Nak-yon, who is running for a parliamentary seat in Jongno district, visited a shop in the area to win voters' support.

The DP and its satellite party -- the Civil Together - plan to hold a joint ceremony marking the official launch of their election campaigns at the National Assembly on Thursday afternoon.

The head of the main opposition United Future Party Hwang Kyo-ahn, who is also running in the Jongno district, held a news conference around Wednesday midnight at Gwanghwamun Square in central Seoul to announce his resolve to win the election.  

Candidates from other minor opposition parties, including the Justice Party and the Party for People's Livelihoods, also launched election campaigns in earnest.