Geneva - Mining giant Glencore said on Monday it had struck a deal worth nearly $1bn to purchase shares of two mines in the Democratic Republic of Congo from a controversial Israeli magnate.Switzerland-based Glencore said it will pay Israeli billionaire Dan Gertler's Fleurette group $960m for Fleurette's 31% share in the Mutanda mine and 10.25% stake in the Katanga mine. Glencore, widely regarded as a maverick in the global commodities sector, will assume full control of the Mutanda mine and 86% of Katanga once the deal for the cobalt and copper assets is finalised. The partnership between Glencore and Gertler in DRC has been closely watched, following allegations that the Fleurette chief paid bribes during his dealings in the country. Watchdog Global Witness has described Gertler as a close friend of Congolese President Joseph Kabila and accused him of involvement in a series of shady deals in the country, where corruption has been endemic for decades. "This deal raises yet more serious questions for Glencore over its decade-long business partnership with Gertler," Global Witness said in a statement on Monday. Gertler was reported to have befriended Kabila's father Laurent, who toppled long-serving dictator Mobutu Sese Seko in 1997, turning his ties to the family into mining riches. Joseph Kabila took power following his father's assassination in 2001. Global Witness blasted Gertler, saying he was "cashing in on assets acquired in dubious circumstances" while deeply impoverished DRC "gets nothing from this huge deal".According to the Bloomberg news agency, Glencore may have been anxious to end its partnership with Gertler to protect itself from the political uncertainty shaking the Kabila regime. The Congolese president is facing unprecedented pressure to stand down after his second and final term expired in December.As political tensions soared, he struck a power-sharing deal with the opposition on New Year's Eve that provides for elections late this year.