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SHENZHEN, China, April 28 (Reuters) - Former Huawei unit Honor posted the fastest growth in China's smartphone market in the first quarter, even as overall handset sales fell 14% year-on-year to levels close to those seen in the pandemic-ravaged first quarter of 2020.

Android handset brands Vivo and Oppo, both under the privately owned BBK Electronics, claimed the largest share of first quarter sales, with 19.7% and 18% of the market respectively, research firm Counterpoint Research said.

Apple, which was China's top-selling vendor in the previous quarter for the first time in six years thanks to the release of the iPhone 13, was the third-largest seller in Q1, claiming 17.9% of the market.

Honor made the biggest gains in Q1, taking the fourth biggest slice of sales with 16.9%, with sales up 15.5% on the previous quarter. Huawei Technologies sold its Honor unit in December 2020 to a consortium of agents and dealers as U.S. sanctions crippled the parent's smartphone sales.

Huawei, once China's best selling brand, held 6.2% of the market in the first quarter.

Chinese retail sales lagged in the key coastal economic regions of Guangdong and Jiangsu in the first quarter, with areas hit by COVID-19 outbreaks also showing particular weakness, regional data showed. (Reporting by David Kirton; Editing by Richard Pullin)