(Updating to add details about other reserves in paras 3, 4 and 9)
NEW YORK, Aug 21 (Reuters) - Colombia slashed its gold holdings by two-thirds in July, adjusting its reserves for the first time in years, and Russia continued to buy bullion as spot prices sank in a bullion rout, International Monetary Fund data showed on Friday.
The South American country slashed its gold holdings by 6.5 tonnes, leaving just 3.77 tonnes, the data showed. It was the first time in at least two years the country had changed its reserves of bullion.
Russia bought bullion for the fifth straight month, adding 13 tonnes of gold to its reserves and taking its total to 1,288 tonnes in July, while Kazakhstan and Belarus each added 2.5 tonnes, taking their holdings to 208 tonnes and 47.3 tonnes respectively.
Ukraine increased its reserves by 2.2 tonnes to 26.1 tonnes.
The moves came as institutional and speculative investors pulled more cash en masse from commodities, ending a decade-long boom, as the stock market crash in China reignited concerns about demand from the world's biggest consumer of industrial raw materials.
The year-long rout in oil has hurt economies that are reliant on natural resources, like Colombia.
Spot gold prices had their worst month in July since June 2013, dropping over 6.5 percent to 2009 lows, even after months of calm amid the Greek debt crisis, the stronger dollar and expectations of a U.S. interest rate increase.
A sudden one-day sell-off on July 20 captured most traders' attention. The equivalent of 13 tonnes of gold were sold in New York in seconds in early Asian trading on that day.
China added 666 tonnes of gold to its holding, taking the total to 1,720 tonnes following Beijing's recent disclosures about its gold buying over the past six years, the data showed.
The data also showed Turkey lowered its reserves by 4.8 tonnes in June to just under 500 tonnes. (Reporting by Josephine Mason; Editing by Nick Macfie and Raissa Kasolowsky)