US crude oil inventories fell by more than expected in late September, dropping by 4.34mbbl, reported the American Petroleum Institute (API).

According to several US news outlets, analysts had expected a drop of just over 1mbbl.

For the prior week, the trade association for the oil and natural gas industry reported an increase of almost 2mbbl in crude inventories.

API data also indicates that so far this year, inventories are now at a level around 15mbbl under where they were at the start of the year.

The US Strategic Petroleum Reserve (SPR) reported earlier this week that it had seen its levels rise by 1.3mbbl as of 20 September, now standing at 382mbbl, a substantial rise from the low levels seen in the summer.

In July, the US DOE reported it was seeking up to 4.5mbbl of oil for the SPR from October through December.

Additionally, the department was arranging the return of nearly 4mbbl barrels of exchanged oil as part of its plan to replenish the SPR, aimed at helping “bring down prices for American consumers and businesses”.

The department offered to purchase oil to restock the SPR in July, with US Energy Secretary Jennifer Granholm saying in June that the department could quickly replenish the SPR this year.

In mid-August, the API reported that US crude storage levels had remained relatively stable.

The body reported that crude levels rose by 347,000 barrels for the week ending 16 August, as part of a survey of oil storage facilities and companies.

However, in the previous week, the organisation reported a fall in stocks of 5.2mbbl.