Oil prices recorded a slight increase today, after the United States threatened to maintain the naval blockade on Iran indefinitely, which led to renewed concerns about crude oil supplies, after prices fell in the previous session against the backdrop of expectations of weak global demand, according to Reuters. Brent crude futures rose nine cents, or 0.1 percent, to $87.16 per barrel by 0130 GMT, while US West Texas Intermediate crude futures increased four cents to $81.29 per barrel.