After three cargo ships were hit in Russian missile strikes on Ukrainian ports this week, killing at least 10 and injuring several others, maritime analysts are warning that ship operators could start refusing to transit that stretch of the Black Sea due to the increased threat. 

"If attacks continue, it will eventually force some of the companies to review the policy of calling at Ukraine," said Tomas Alexa, lead analyst for Europe with Ambrey, a firm that assesses and manages maritime risk.

"It seems that there is a change in modus operandi [for Russia] ... there's a green light in attacking directly the ships in port."

As a result of the strikes, which were carried out over five days this week, war risk insurance premiums — a fee shippers must pay when they cross through high-risk areas — have increased in this section of the Black Sea by as much as 30 per cent, Alexa said.

Russian officials, along with some state-affiliated media, have claimed the ships were targeted because they were carrying ammunition and military equipment. 

Ukraine, and at least one of the shippers, denies these claims, saying all of the vessels were exporting commercial goods.

Could harm ability to export

Ukraine worries this could erode its ability to export its agricultural products, including grain and corn, along a temporary export corridor. 

After Russia pulled out of the Black Sea Grain Initiative, a deal brokered by the United Nations and Turkey that set up a humanitarian shipping corridor, Ukraine established its own temporary route. 

Instead of crossing the sea directly, the vessels now hug the coastlines of two NATO countries, Bulgaria and Romania, as they make their way to Ukrainian ports.

Three different ports were hit during this week's attacks.

Russia's Ministry of Defence said it targeted a cargo ship at Pivdennyi, Ukraine, on Oct. 6, because it claimed the Saint Kitts and Nevis-flagged vessel was carrying ammunition supplies from Europe. 

The ministry released a grainy black and white video that appeared to be taken from a surveillance drone and claimed the footage showed a large explosion, the result of ammunition detonating. 

Ukraine denies these claims and says the ship was carrying 6,000 tonnes of corn. 

The ship, Paresa, is owned by AK Shipping, a company based in Greece. 

Syrian, Indian nationals on board with Ukrainians

Tradewinds, a publication focused on global shipping, spoke to the company's owner, who denied Russia's claims and provided documents that showed it was contracted to carry Ukrainian grain in October on behalf of Swiss clients. 

Russia does "such despicable things as attacking civilian infrastructure and is not afraid to directly attack ships flying foreign flags," said Oleksandr Kharlov, first deputy head of the Odesa regional military administration, in an interview with CBC News.

"Unfortunately, our citizens, port infrastructure workers … who have nothing to do with military affairs or the defence of our country, are dying."

All of the victims killed in the attacks were Ukrainian citizens, but among the wounded were nationals from Syria and India, who were working on board the ship Optima, which was damaged in an Oct. 7 attack on the port of Odesa.  

The third attack hit the port of Chornomorsk on Oct. 9.

In that strike, a Panamanian-flagged container ship, the Shui Spirit, sustained damage, and at least 10 Ukrainians were killed.

The city of Odesa marked a day of mourning on Friday not only to honour the victims in the port strikes, but four who were killed in a building hit by a Russian strike on Thursday night. 

No media access to port

Media access hasn't been granted to the Odesa ports after the attacks, but Ukrainian officials have released photos they say show the aftermath and prove that Russia was targeting civilian infrastructure. 

One of the pictures shows destroyed shipping containers, and what look like boxes of Christmas ornaments scattered on the ground. 

Alexa says while his analytics firm can't completely rule out that the ships are involved in weapons delivery, there is no proof from Russia that they were. 

"Our argument is that Russia has decided that they have to really curb the amount of vessels calling Ukraine," he said.

Ukraine, which is one of the world's major growers of wheat and corn and a major supplier of sunflower oil, has been able to ramp up its exports using the temporary Black Sea route, which is a crucial revenue source for Kyiv. 

But Alexa says these recent attacks will likely make some shippers transiting the route more wary. 

Similar risk for Russia-controlled ports

Since Russia's full-scale invasion began on Feb. 24, 2022, there have been cases where ships have switched crews before entering the Black Sea, as some on board didn't want to make the journey. 

Alexa says companies that have already left the area but are considering returning to it may choose to postpone their plans for now. 

In a risk briefing, Ambrey concluded these recent attacks mean there's also a heightened threat to vessels operating in areas and ports occupied by Russia, because of the possibility that Ukraine could retaliate.

The briefing states that Russia could keep targeting commercial vessels using the pretext that they are supplying weapons.

It suggests the only way to counter such claims would be to allow Russian forces to inspect vessels, as they did under the UN-backed Humanitarian Grain Corridor, a measure Ukraine is unlikely to agree to.