Oil prices rebounded on Tuesday after losses of six consecutive sessions but markets are still under pressure as traders lost confidence that pledges by major producers to cut output would curb the glut of global oil supplies .
By 0640 GMT, the WTI crude futures contract rose 14 cents, or 0.3 percent, to $ 49.37 a barrel, to stay below the $ 50 level it dropped late last week. .
Brent crude was up 14 cents, or 0.27 percent, at $ 51.74 a barrel .
Brent has fallen 10 percent since late 2016, despite efforts by the Organization of the Petroleum Exporting Countries (OPEC) and Russia to cut production by 1.8 million barrels per day in the first half of this year to reduce supply in the oil market .
Russia said on Monday its oil production could jump to a 30-year high unless Opec and independent producers extended a cut production agreement beyond June 30 .