New York: Oil prices rebounded as investors worried about plummeting Nigerian production after a militant attack in Nigeria. The West Texas Intermediate for July delivery on Monday added $1.07 to settle at $49.69 a barrel on the New York Mercantile Exchange, while Brent crude for August delivery gained $0.91 to close at $50.55 a barrel on the London ICE Futures Exchange, Xinhua news agency reported. Output of Nigeria's Bonny Light crude has fallen by an estimated 170,000 barrels per day (bpd) following recent attacks on pipeline infrastructure, according to media reports on Monday. Traders were also encouraged by the speculation that the Federal Reserve will not raise interest rates this month, which will weaken the US dollar and bolster the dollar-priced crude. Fed Chair Janet Yellen said at the World Affairs Council of Philadelphia on Monday that the overall labour market is quite positive, although the recent slowdown in jobs bears "close watching". She said additional rate increases would still probably be appropriate but did not give a specific time period for the next hike.