By Thomas Copeland and Becky Dale The volume of oil flowing from the Middle East region has almost returned to pre-war levels, data shows, despite the continued restrictions Iran is placing on vessels attempting to travel through the Strait of Hormuz.

Seven months after the US-Israel war with Iran led to the effective closure of the critical waterway, the maritime intelligence firm Kpler said that in the final week of September, daily oil flow from the Middle East reached 92% of its pre-war baseline.

Analysts attribute the rebounding flow of oil to three key factors:

Ships being escorted with US military assistance Using shuttle tankers through the strait for transfer to different vessels Bypassing the strait using pipelines But some experts have questioned the sustainability of these measures, given the risk of escalating Iranian attacks or a change in US policy.

About 40% of the total oil exported from the region in September bypassed the strait and exited via overland pipelines to ports on the Red Sea or the Gulf of Oman, up from 17% before the war, according to Kpler.

Oil exports from Iran, however, have ground to a halt after the reimposition of a US naval blockade in July.

The US military has been supporting ships as they pass through the Strait of Hormuz since at least mid-June and US Navy data shows the number of vessels assisted by US forces is up by a third in September compared with August.

Martin Kelly, senior intelligence analyst at security firm EOS Risk Group, told BBC Verify that US support is primarily in the form of "air support to ships", including through issuing warnings and intercepting incoming threats from drones, missiles or boats.

But ships moving through the US-recommended southern route of the strait near the coast of Oman, rather than seeking permission to use Iran's northern route, continue to be targeted.

September saw the highest number of successful Iranian attacks on commercial shipping since March, according to the Armed Conflict Location and Event Data conflict monitor.

Naveen Das, a senior oil analyst from Kpler, said the market oil market "doesn't trust that we're going stay in this status quo" because of the risk of further Iranian escalation and the possible impact of the US midterm elections.

Most of the oil passing through the strait now moves via a "shuttle system" of more than 60 large oil tankers moving back and forth, according to Kpler.

More than 70% of the crude oil which passed through the strait in August was transferred from these "shuttle tankers" onto other vessels in the Gulf of Oman, Kpler said.

BBC Verify has analysed satellite imagery which appears to show these ship-to-ship transfers, seemingly more protected from Iranian attack, taking place off the coast of the Omani port city, Sohar.

But there is a "question over how long these ships can last", said Martin Kelly, particularly as attacks on them continue. Imagery taken on 24 September shows six pairs of ships docked or paired together near the port.

An average of more than four million barrels of oil per day was transferred from ship to ship in the Gulf of Oman over in the week to 30 September, according to Kpler.

Overall, an average of 12 million barrels of oil per day passed through the strait over this period, compared with a pre-war baseline of 17 million.

Oil exporting countries in the Gulf have also responded to Iranian attacks in the Strait of Hormuz by exporting more crude oil overland via pipelines.

Just under 20% of crude is now leaving the region from ports on the Red Sea at the end of Saudi Arabia's East-West Pipeline, which is recording exports of more than four million barrels per day, according to Kpler.

Three weeks after an attack on this pipeline blamed on Iran-backed proxies in Iraq, Saudi Arabia is now exporting through the pipeline at "full stretch", according to Kpler.

Almost a quarter of all crude flowing from the region is now being piped past the Strait of Hormuz to terminals along the Gulf of Oman, particularly the city of Fujairah in the United Arab Emirates (UAE), Kpler's data shows.

Naveen Das from Kpler said this increased use of pipelines is likely to become the "new normal" because "it seems very improbable that we live in a world whereby the Gulf countries and Iran go back to being relatively harmonious".

Oil exports from Iran have fallen almost to zero following the re-imposition of a US blockade in mid-July, down from 1.7 million barrels a day before the war began, Kpler data shows.

There are 20 empty Iran-flagged tankers currently off the coast of Sri Lanka, unable to return to the Gulf due to the US blockade, according to ship-tracking data and analysis from the US-based advocacy and monitoring organisation United Against Nuclear Iran.

While crude oil flow from the Middle East has resumed to almost normal levels, exports of liquified natural gas and oil products like jet fuel and have remained well below pre-conflict volumes.

Fewer than a million barrels of processed oil products passed through the Strait of Hormuz on average in the last week, down from 3.5 million per day before the war began. What do you want BBC Verify to investigate?