Inflation has risen to 3.7% in the year to September, which is a higher-than-expected increase fuelled by petrol prices.

Vehicle fuel prices jumped by 34.2% over 12 months.

In September alone, they jumped by 9.1%, accounting for more than half of the increase in inflation, according to the Bureau of Labor Statistics.

Overall, energy inflation was up by 20.4% over the year as prices for fuel oil, energy services and electricity climbed. Fuel oil, used in home heating, was up 74.2% over the year.

Experts said the US Federal Reserve - which sets the country's interest rate - will be closely watching to see if energy costs begin to affect other areas of the economy, such as food prices, and drive inflation higher.

At the moment, food inflation remains subdued. It was flat over the month of September, and was 2.5% across the year.

Core inflation, which strips out food and energy prices, was 2.6%.