BEIJING-- Cisco Systems Inc. plans to remove several of its senior executives in China, as sales slide because of government fears about the security of foreign networking equipment, people briefed on the matter said.

The shake-up flattens the China organizational structure and falls in line with a global reorganization at Cisco after longtime Chief Executive John Chambers announced last month he would hand the reins to another Cisco veteran, Chuck Robbins.

Mr. Robbins has said he wants a structure that can make decisions more quickly. This month he shrank his core management group from 13 members to 10, eliminating a layer of presidents.

Several senior executives in China have been asked to step down, including Hahn Tu, Cisco China president, and Fredy Cheung, vice president in Greater China, people briefed on the matter said. Neither could be reached for comment. It wasn't immediately clear whether the positions will be eliminated or if they will be replaced.

Cisco Greater China Chairman Owen Chan will remain, the people said.

Cisco's China sales fell 20% in the quarter ended April 25 from a year earlier, compared with the company's 5.1% global revenue gain. Its share of the router market in the country fell to 9.4% in the first quarter from 21.2% a year earlier, with the lost sales going to local rival Huawei Technologies Co., according to Bernstein Research.

The sales decline is largely due to the Chinese government's efforts to shift to local technology after former U.S. National Security Agency contractor Edward Snowden alleged in 2013 that the NSA covertly put surveillance tools in some U.S. technology products sold overseas, people familiar with the matter said.

Cisco is grappling with broader challenges, such as rising competition from software-based alternatives to its hardware.

Mr. Robbins said in a blog post on June 4 he planned to look outside the company to fill several key jobs to build Cisco's position in new markets.

Ted Greenwald contributed to this article.

Write to Eva Dou at eva.dou@wsj.com

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