US and UK forces shot down 18 drones, two anti-ship missiles and a cruise missile on Tuesday night in the biggest-yet Houthi barrage on commercial shipping. 

There were no injuries or damage reported in the attack, the 26th in the Red Sea since November 19 and the most serious yet in the nearly month-long maritime security crisis.

F/A-18 fighter jets from four US and one British warship shot down the drones and missiles.

Several vessels have changed course while transiting the Red Sea amid multiple reports of aerial drones about 50 nautical miles off Houthi-controlled Al Hodeidah.

The incident was first reported by UKMTO at 1915 hrs UTC.

A “Yemeni military source” told Al Jazeera Arabic that the militants had targeted an Israel-linked ship in the Red Sea, the outlet reported.

It reported dozens of merchant ships were transiting the shipping lane at the time. Centcom did not say which ships were the intended targets. 

The incident is the third since a US-led coalition of 13 nations warned the Houthis to cease their attacks or face consequences.

Shipping lawyer Stephen Askins said: "In light of the recent warning by the US/UK et al we wait to see whether the 'allied' forces will now take action ashore."

He said the the naval presence meant there was “clearly” an effective missile screen, but the anti-ship cruise and ballistic missiles have ranges up to 800 km and can carry a warhead with 400 kg of explosive. 

"The navy are not stopping the missiles from being fired and nor is there any indication that they could," he said on LinkedIn.

"Further, they are not constrained to the Red Sea which makes you think that what the Yemenis may really want is a successful strike on a warship."

The Houthis have said they don't want to sink commercial ships but ran a serious risk of collateral damage if this was truly their aim, he added. 

The US has considered strikes on Houthi targets ashore but has so far been reluctant to escalate tensions in the region. Saudi Arabia, which has fought the Houthis for years, has also urged restraint as it seeks to protect a fragile ceasefire with the Yemeni rebel group.

But the US and other countries in the Operation Prosperity Guardian taskforce will face growing pressure to respond to the latest attack.

The attacks had appeared to subside in recent weeks, perhaps because of lack of targets as Western containerships avoided the Red Sea for the longer Cape of Good Hope route. Tanker traffic has continued much as normal so far and oil prices have largely shrugged off the crisis.

Shipping companies’ willingness to transit the Red Sea has so far come down to their own risk appetite.

Askins, a partner at Tatham & Co and former British Royal Marine with expertise in piracy and marine terrorism, said the presence of warships made it harder to assess risk for individual ships, particularly where small convoys were offered.

Navies could be a “huge factor” in deterring boardings but this was not the only threat. 

“The test under the more recent war clauses is to ask whether the vessel may be or is likely to be exposed to war risks,” Askins said.

“Clearly being a vessel with Israel connections increases the risk of being targeted but that is not the test.

“Under the older clauses, whether an owner can refuse orders to proceed through a place of danger involves a more nuanced look at the danger and the likelihood of attack.”

Maritime security firm Ambrey said it received reports of suspicious activity from two merchant vessels located southwest of Mokha, Yemen.

A tanker reported seeing flares or missile trails, while a bulker identified three small ships around one mile off its port quarter.

“Ambrey assessed this event was separate from an incident that was reported west of Hodeidah around the same time,” the company said.

The company advised merchant ships traversing the area to minimise crew movements on deck, and recommended that only essential personnel remain on the bridge in case of falling debris.

Vespucci Maritime chief executive Lars Jensen said on LinkedIn on Wednesday morning some shipping lines appeared undeterred from the area. There were four containerships about to enter the transit at regular speed and another six having a transit in progress, he said.

“There might be additional vessels in the area with AIS turned off — possibly vessels from CMA CGM, and also the US-flagged Maersk Atlanta which has now had AIS turned off for seven days since transiting the Suez Canal,” Jensen said. 

Visible containerships appeared to be from smaller niche carriers such as Russia’s Fesco and SeaLead Shipping, based in Singapore.

“The magnitude of yesterday's attack is likely to reinforce the global carriers’ position that the passage is too risky,” Jensen said. 

“On the positive side it can be argued that despite the attack, the military managed to neutralise the drones and missiles. On the negative side it shows the Houthis are both willing and capable of not only continuing the attacks, but also increasing the magnitude of the attacks.¨