Insurance costs for Red Sea shipping have more than doubled following Yemen's deadly attacks that sank two vessels and killed at several ship workers in recent days.

War risk premiums have surged to around 0.7% of a ship's value from approximately 0.3% last week before the latest attacks, with some underwriters pausing cover for certain voyages, industry sources told Reuters on July 10.

Rates for typical seven-day voyage periods have been quoted at up to 1% this week, matching peak 2024 levels when daily attacks occurred. This adds hundreds of thousands of dollars in additional costs for every shipment through the critical oil and commodities route.

A Houthi attack on the Greek ship Eternity C on Wednesday killed four of 25 people aboard, with rescuers pulling four more survivors from the Red Sea on Thursday. Houthi militants said they were holding some crew members still missing.

The attack followed Monday's sinking of another Greek-operated vessel, which the Houthis claimed responsibility for. Analysis of shipping data showed some sister vessels had called at Israeli ports in the past year.

The Iran-aligned group has attacked more than 100 ships since November 2023 in what they said was solidarity with Palestinians in the Gaza war. Traffic through the Red Sea has dropped sharply since the campaign began.

The United States announced a deal in May to stop bombing the Houthis in return for ending shipping attacks, though the Houthis said the agreement did not include sparing Israel.

Insurance industry sources said underwriters would try to avoid covering any vessel with Israeli links, even indirect ones.

"What we have seen in the last week appears to be a return to mid-2024 targeting criteria, which essentially involves any vessel with even a remote Israeli connection," said Munro Anderson, head of operations at marine war risk insurance specialist Vessel Protect.