Seoul Mayor Park Won-soon called Tuesday for a swift and thorough prosecution investigation into the intelligence agency's alleged illegal campaign against him and urged public institutions to stop intervening in politics.

Last month, allegations surfaced that the National Intelligence Service (NIS) wrote documents in 2011 instructing its employees to suppress Park's political influence. The civic activist-turned-mayor is affiliated with the main opposition Democratic Party.

The report, titled "the left-wing tendencies of Seoul Mayor's governance and how to counter them," also outlines a plan to mobilize ruling party figures, government agencies and academies for its political schemes to "subdue" Park, drawing public outcry against the NIS already under fire for its alleged meddling in last year's presidential election.

"It is inconceivable that the prosecution does not carry out thorough investigations into such a retrograde issue that reminds us of the Yushin Constitution era. It will lead to a public outcry," Park said in an interview with Yonhap News Agency.

Yushin, or revitalizing reform, refers to a new constitution introduced by the military-backed regime of late former President Park Chung-hee, which critics said was aimed to suppress the pro-democracy movement in the 1970s and to perpetuate his rule.

"I think the document along with thousands of negative comments about me online that the NIS allegedly created will be just the tip of the iceberg. I can see them being quite intentional," Park said, calling on government agencies to stop meddling in politics.

Speaking of his being cited as a presidential candidate, Park stressed his commitment to serving his current position.

"(Being encouraged as a presidential candidate) would make me excited, but I've seen many cases where that rather ruins everything," Park said. "My sole goal is to make Seoul the world's most desirable and happiest city in the 21st century."

Asked about the progress in his pledges to push for inter-Korean cultural exchanges by hosting football friendlies and staging a performance by the Seoul Philharmonic Orchestra in North Korea, he reiterated his willingness for the drive but took a cautious stance.

"Despite my will, those measures can be pushed for after we break the deadlock in the inter-Korean relations," the mayor said, advising the central government to begin talks with North Korea about "softer issues such as sports and art than political ones." 

Park complained that the central government is "killing" the local administration by shouldering heavy burdens for state projects and asked it to increase financial support for new welfare programs. 

"The central government has created diverse measures, earning political credit, and had local governments implement them. But it lacks budget planning and is emptying our coffers," Park said. "It is hard for the Seoul city to afford the bills for the new free day care programs."

Under a revised law, all households with children under the age of five are entitled to receive subsidies from this year, which requires an additional 371.1 billion won ($320.6 million) for Seoul alone. Previously, those raising children under the age of three and aged five received the subsidy, but for households having children aged three and four, only families in the bottom 70 percent income bracket received it. (Yonhap News)