Oil prices drop 5% to three-week low in Tuesday trading

Oil prices fell more than 5% at the close of trading today, reaching their lowest levels in three weeks.

Brent crude futures dropped $4.41, or 5.3%, to settle at $79.36 a barrel, the lowest since July 13. US West Texas Intermediate crude fell $4.57, or 5.7%, to $75.77 a barrel, also marking a three-week low.