March 5 (Reuters) - Russian gold and silver producer Polymetal International Plc said on Monday:
* The company increased its ore reserves by 5 percent in 2017 to 20.9 million ounces of gold equivalent.
* Gold reserves were 5 percent up at 18.4 million ounces, while silver reserves decreased by 3 percent to 158 million ounces last year.
* The company expects 2018 to result in further significant extensions of reserves and resources. Source text for Eikon: Further company coverage: (Reporting by Moscow newsroom)