Oil prices extended losses on Monday as Saudi Arabia and Russia said they may increase supplies while U.S. production gains show no signs of slowing.  Brent crude futures LCOc1 stood at $75.35 a barrel at 0913 GMT, down $1.09 from the previous close and after touching a three-week low of $74.49 earlier in the session. U.S. West Texas Intermediate (WTI) crude futures were at $66.69, down $1.19, after hitting a six-week low of $65.80. The Organization of the Petroleum Exporting Countries (OPEC) and other producers led by Russia began withholding 1.8 million barrels per day (bpd) of supplies in 2017 to tighten the market and prop up prices that in 2016 fell to their lowest in more than a decade at less than $30 a barrel. […]