Oil prices climbed Tuesday as Iran clamped down on anti-government protesters and unrest in the Middle East threatened to keep energy prices high for months to come.

West Texas Intermediate for April delivery, a benchmark North American crude, gained $2.66 to settle at $99.63 per barrel on the New York Mercantile Exchange. In London, Brent crude — a benchmark used widely outside North America — gained $3.62 to settle at $115.42 per barrel on the ICE Futures exchange.