The cost of transporting fuels on key trade routes is soaring as attacks on Red Sea shipping ripple out into global markets.

The day rate for shipping a cargo of gasoline from northwest Europe to the US east coast has almost tripled since the start of the year, nearing $38,000 a day on Monday, according to data from the Baltic Exchange. Fleet use is up 2.5 percentage points from the average in the fourth quarter, according to an estimate from Clarksons Securities analysts including Frode Morkedal.

“This uptick is partly due to rerouting ships around Africa, leading to reduced availability for spot cargoes,” they wrote in a report earlier on Monday.

Several oil product tanker companies have said they will no longer carry cargoes through the Red Sea in response to the attacks on merchant shipping by Houthi militants. Vessels including the Almi Globe are sailing the long way around Africa instead of passing through the danger zone.

Hauling fuel from the Middle East to Japan has gone up by two thirds in a week, the Baltic Exchange’s data show.

The longer journeys mean there are fewer ships available in the spot market to pick up cargoes, restricting vessels supply.