Yemen’s Houthi rebels conducted the largest number of attacks on commercial ships so far in 2024 in June, fresh proof that the group’s threat to trade intensified in recent weeks. 

There were 16 confirmed attacks on ships in June, according to figures published by the naval forces operating in the region. That’s the most for any single month in 2024, and was only eclipsed in December when more vessels were still sailing through the region. Separate figures published by the Washington Institute show a similar trend. 

Attacks by the Houthis ramped up in June, having shown signs of diminishing in the preceding months. The incidents included the second confirmed sinking of a vessel, as well as the first successful attack with a seaborne drone. The attacks are helping to contribute to the second-largest increase in a gauge of global sea transport on record as vessels sail thousands of miles extra around Africa. 

Tracking the exact number of incidents can be tricky as different agencies use different definitions for attacks. Some may also go unreported.