Russian President Vladimir Putin and Saudi Arabia’s Crown Prince Mohammed bin Salman agreed in a phone call to continue cooperation on the oil market, according to Russian sources. “The importance of further coordination within the framework of OPEC+ was stressed,” the Kremlin said on its website on Thursday. US President Joe Biden had also visited bin Salman only this week as part of his Middle East trip to try to persuade Saudi Arabia to increase oil production in a bid to push down oil prices on the world market. The results of Biden’s trip to bin Salman, long ostracized by Washington for h…