NEW YORK, Oct. 14 (Xinhua) — Oil prices ended lower on Friday amid a stronger greenback and rising oil rigs in the U.S.

A stronger U.S. dollar made the greenback-dominated oil less attractive for holders of other currencies. The dollar index, which measures the greenback against six major peers, was up 0.38 percent at 97.883 in late trading Friday.

Meanwhile, oil company Baker Hughes reported on Friday that U.S. drillers added four oil rigs in the last week, marking the 15th increase in 16 weeks.

The total number of oil rigs operating in U.S. fields stood at 432, compared with 595 at this time last year.

The West Texas Intermediate for November delivery lost 0.09 U.S. dollars to settle at 50.35 U.S. dollars a barrel on the New York Mercantile Exchange, while Brent crude for December delivery decreased 0.08 dollar to close at 51.95 dollars a barrel on the London ICE Futures Exchange.