By Sinead Carew NEW YORK (Reuters) – Cisco Systems Inc warned its revenue would dive as much as 10 percent this quarter, and keep contracting until after the middle of 2014, as a backlash against U.S. government spying contributed to plummeting demand in emerging markets like China. The hit comes after former U.S. spy agency contractor Edward Snowden exposed widespread surveillance by the National Security Agency – in particular through Internet data, much of which is transmitted via Ciscos network equipment. Chinas Ministry of Public Security was reported in August to be on the verge of launching a probe into Cisco rivals including IBM Corp, Oracle Corp and EMC Corp over security issues. Cisco shares fell more than 10 percent in late trade after it also missed its revenue target for its fiscal first quarter just ended, where it saw a big drop in sales to telecom and cable service providers as well as in emerging markets.