Urgent action is needed, they say, as traders are using the Middle Eastern political turmoil as a ruse to artificially inflate the price of oil.

The politicians asked the watchdog to “restore the integrity to our energy markets” by “requiring higher margins of speculative positions.”

They said the CFTC’s own evidence demonstrated the need for action, as the number of speculative positions was increasing. “The Commitment of Traders Report reveals that speculators have flooded into the market in recent weeks,” they said. “Since protests began in Egypt on January 25, money managers have increased their long positions in Nymex West Texas Intermediate crude oil futures contracts by more than 35%, or the equivalent of 75m barrels of oil,” the senators wrote.

“Oil speculators have increased long positions on Intercontinental Exchange by nearly 50%. At the same time, actual true hedgers have reduced their long positions in the oil futures markets.”

The letter said now was the time to exercise the CFTC’s authority under the Dodd-Frank Act to mandate position limits and higher margins for speculative trades.

The regulator is unlikely to change its schedule for making policy on position limits. Its proposal is already going through a second public comment period. Eight thousand letters were received during the first period, and 3,690 have come in during the second.

The vast majority support position limits, but many are from private individuals. Big futures brokers and exchanges tend to oppose the policy, which could reduce trading volume.