The price action for crude mirrored movements of the broader markets during the morning hours of trading with both down more than one percent relative to Friday's close.

Light, sweet crude for March delivery on the NYMEX retraced the early morning trading losses prior to the lunch hour, only to falter and settle 0.8 percent, or 78 cents, lower at $98.78 per barrel. Natural gas followed a similar pattern to WTI crude, but with a little more volatility. Natural gas for March delivery lost 1.6 percent, or 4.3 cents, to settle at $2.713 per MMBtu.

Among refined products, February reformulated gasoline blendstock fell 1.9 percent, or 5.6 cents, to $2.87 per gallon, coming off a close Friday that was at its best level since August 2011.

Brent also was down once the US markets opened. While fears surrounding the tensions with Iran and a possible supply disruption buoyed prices, fundamental pressures due to perceptions of waning demand were a stronger force across the energy complex, leading to overall losses during the trading day with Brent falling $0.71, or 0.6 percent, to $110.75 a barrel.