Gram Car Carriers is the latest shipowner to back out of the Red Sea.

The Oslo car carrier lessor said on Thursday that it has notified charterers that its ships are restricted from passing through the Red Sea to ensure the safety of crew, cargo and ships amid a string of attacks by Houthi militants in Yemen.

“This is due to the increased risk levels in the area as reflected in the Norwegian Maritime Authority raising the security level in the southern part of the Red Sea to the highest level,” the company said in a statement.

“[Gram Car Carriers] monitors the situation closely and will review and update this policy when appropriate based on recommendations from relevant authorities.”

The Georg Whist-led company follows similar decisions from fellow compatriot car carrier owners Wallenius Wilhelmsen and Hoegh Autoliners.

Wallenius Wilhelmsen was the first to make the call on Tuesday, with Hoegh Autoliners following on Wednesday concurrent with the Norwegian Maritime Authority’s decision to raise the threat level for the southern Red Sea area to level 3.

The highest level, level 3 dictates that ships can transit the area at their owners’ discretion, but cannot make port calls in the area.

Unlike Wallenius Wilhelmsen and Hoegh Autoliners which deal directly with automakers, Gram Car Carriers charters its 23 ships — 19 owned and four managed — out to car carrier operators.

Shipowners began pulling out of the region on 15 December with container shipping giants AP Moller-Maersk and Hapag-Lloyd following an unsuccessful missile attack on the 10,100-teu Maersk Gibraltar (built 2016) the day prior.

Other major liner players like MSC Mediterranean Shipping Co, CMA CGM, Yang Ming Marine and HMM followed, as did tanker owners Frontline and Euronav.

Tensions in the region rose in mid-November, when the 5,100-ceu Ray Car Carriers-owned Galaxy Leader (built 2002) was hijacked. The company’s principal is Israeli.

Attacks became more frequent in December when the Iran-backed Houthis said they would attack any ship with connections to Israel.

On 12 December, J Ludwig Mowinckels Rederi’s 20,000-dwt Norwegian-flagged Strinda (built 2006) was hit with an anti-ship missile with the Houthis alleging the vessel was heading to Israel.

The next day, the 49,500-dwt Ardmore Encounter (built 2014) was briefly boarded and was fired upon.

In an effort to combat the attacks, the US launched a naval effort known as Operation Prosperity Guardian.

Norway is one of nine countries participating in the mission, potentially raising the stakes further for Norwegian ships as Houthi Abdul-Malik al-Houthi said on Wednesday those countries’ shipping interests were now considered targets.

Other Operating Prosperity Guardian members include the UK, Bahrain, Canada, France, Italy, Netherlands, Greece, Seychelles and Spain.