SHANGHAI, Aug 17 (Reuters) - Internet and securities watchdogs in China"s financial hub Shanghai have waged a campaign against "black mouths", commentators who try to manipulate stock prices with online posts, the cyberspace regulator said in Tuesday. During the recently launched campaign, the Shanghai offices the Cyberspace Administration of China (CAC) and China Securities Regulatory Commission (CSRC) deleted or blocked over 17,000 pieces of harmful information and dealt with more than 8,000 illegal accounts, CAC said in a statement. CAC Shanghai has also urged local Internet platforms such as Bilibili Inc and East Money Information Co (300059.SZ) to strengthen their content oversight. The campaign is part of China"s push for tighter regulation of the tech industry and greater scrutiny over online financial information flows. CAC Shanghai said fake and misleading information spread via Internet platforms by "black mouths" triggered boom-and-bust moves in stocks, seriously disturbing economic and social order. Regulators will also remove other harmful posts involving illegal stock recommendations and underground margin lending, the statement said.