U.S. energy firms added one oil rig this week, the sixth consecutive week of increases even as U.S. oil prices flirted with 6-1/2-year lows, signaling further pressure on a market awash with crude.

Reflecting plans announced in May and June, when U.S. crude futures averaged $60 a barrel, drillers added one oil rig in the week ending on Aug. 28, bringing the total count up to 675, the highest since early May, oil services company Baker Hughes Inc said on Aug. 28 in its closely followed report.