MOGADISHU: A US-sanctioned oil tanker hijacked by Somali pirates last month has been rescued after being chased down and ambushed by maritime police, officials in the semi-autonomous Puntland region said on Friday.

There has been a resurgence in Somali piracy since April, with at least 15 attacks this year, the highest since 2013, according to the International Maritime Organization.

The Seamull tanker, also known as Sibu 1, is sanctioned by the US as part of Iran’s “shadow fleet,” accused of secretly exporting Iranian oil.

It was seized by pirates off the coast of Yemen on August 20 and brought to Somali waters.

Puntland authorities said they had started pursuing the tanker earlier this week, along with three others being held offshore near the town of Bander Beyla, forcing the pirates to head south along the Somali coast.

“While they were anchored south of Garacad, a large ship used by Puntland ambushed Sibu 1 out at sea,” a security official said.

“Sibu 1 was caught off-guard,” added another official.

One pirate was killed, four wounded and 15 captured in the operation, while the 20-strong crew was safely rescued, Puntland authorities said in a statement, adding that one police officer was injured.

The three other hijacked tankers — Honor 25, MT Eureka, and MT Asana — are still being held by pirates, who have moved south toward the port town of Hobyo, part of neighboring Galmudug state, the officials said.

Honor 25 and MT Eureka were carrying fuel worth millions of dollars, they said, and pirates had been observed off-loading barrels to sell on the black market.

Piracy was rampant off the coast of Somalia in the 2000s and peaked in 2011 before being curbed by international naval deployments and new security measures for commercial shipping.