Concerns have grown over an uptick in Somali pirate attacks against cargo ships, after four vessels were targeted in a single week in April.

BBC News reports that the U.K. Maritime Trade Operations (UKMTO) has raised the threat level off the coast of Somalia to "substantial," meaning that attacks on ships in the area are a "strong possibility." Most recently, a cargo ship was taken over by suspected pirates on April 26 and redirected into Somalia's territorial waters. The UKMTO reported that pirates seized a Somali-flagged fishing vessel on April 23 as well, but were turned away in a separate incident that same day, when two armed men unsuccessfully attempted to board a cargo ship from a small boat. 

Somali pirates also hijacked the Honour 25, a Palau-flagged oil tanker, off the Somali coast on April 21. The tanker was said to be carrying 18,500 barrels of oil, with 17 crew members, and has yet to be recovered by authorities. This comes as shipping companies have already had to account for security issues created by the ongoing closure of the Strait of Hormuz, as well as a resurgence of Houthi attacks on commercial vessels in the Red Sea.

Although piracy had largely been suppressed over the past decade, the scaling back of security measures and renewed geopolitical instability have created an opening for attacks to return over the last three years. Moving forward, vessels traveling through the stretch of the Indian Ocean near the Somali coast are being advised by the UKMTO to transit the region with caution.