Around a fifth of global crude oil and liquefied natural gas (LNG) passes through the waterway in peacetime.

The war erupted on February 28 when the United States and Israel began bombing Iran, prompting Tehran to retaliate with strikes across the region and restrict access to the strait.

- 27 ships targeted -

In total 27 commercial ships, including 13 tankers, have been attacked or reported incidents since March 1 in the Gulf, the Strait of Hormuz, or the Gulf of Oman, according to British marine security agency UK Maritime Trade Operations (UKMTO).

In the latest incident, a tanker leased to Qatar's state-owned energy company was struck by an Iranian missile in the Gulf country's territorial waters, officials there said Wednesday.

- 11 sea workers killed -

Since the conflict began, at least 11 seafarers or dock workers have died in incidents in the region, according to the International Maritime Organization (IMO).

The UN agency updated that tally Tuesday, after formally confirming the deaths of three seafarers aboard the Thai bulk carrier the Mayuree Naree, which was attacked while transiting the strait on March 11.

- Handful of crossings -

Just a handful of vessels crossed the strait on Wednesday and Thursday, according to maritime intelligence firm Kpler.

Since March 1, commodities carriers have made 225 crossings, according to Kpler data, a 94-percent decrease on peacetime.

Of these, 139 were by oil tankers and gas carriers and most were travelling east out of the strait.

Six out of 10 crossings involved ships coming from or heading to Iran.

The other main countries involved in recent days were the United Arab Emirates, India, China and Saudi Arabia.

The channel in peacetime sees around 120 daily transits, according to shipping industry intelligence site Lloyd's List.

- 2,000 ships in Gulf -

Bloomberg data showed Thursday that 2,163 vessels sent transponder signals in the Gulf west of the Strait of Hormuz over the past day -- including 308 oil and gas vessels.

- Iran-approved route -

Recent crossings appeared to have mainly used a route apparently approved by Iran around Larak Island just off the country's coast.

Analyst Bridget Diakun of leading shipping journal Lloyd's List estimated 63 ships had used it in the past two weeks.

She said there had been at least two cases of shippers paying Iran for permission to pass, while others may have been gaining passage through "diplomatic negotiations".

The Revolutionary Guards said the route was closed to vessels travelling to and from ports linked to Iran's "enemies".

- 46% sanctioned ships -

Since the war started, 46 percent of the crossings have been by ships under US, EU or UK sanctions, according to an AFP analysis of passage data.

Of the crossings by oil and gas tankers, 64 percent were by vessels under sanctions.