Somali pirates have hijacked an Iranian vessel carrying 21 Iranian fishermen and two Somali security guards in waters off the northeastern coast of Somalia, according to the European Union’s Maritime Security Centre Indian Ocean (MSCIO).

The vessel was hijacked on Thursday between the coastal towns of Bandar Bayla and Hafun in northeastern Somalia, a maritime security officer with the Puntland Maritime Police Force said on Sunday.

The security officer added that 12 pirates had boarded and seized the Iranian vessel. The officer spoke on condition of anonymity, citing a lack of authorization to speak to the media.

The fate and safety of the 23 crew members remain unknown, according to an MSCIO alert issued on Saturday.

In an updated warning, the maritime security center said the pirates could use the hijacked vessel as a “mother ship” to support further attacks on commercial shipping.

The European Union’s naval Operation Atalanta is investigating the incident, while MSCIO has urged vessels operating in the area to exercise heightened vigilance and report suspicious activity.

The hijacking comes amid a renewed resurgence of Somali piracy across the Gulf of Aden and the western Indian Ocean, threatening the safety of fishermen, commercial vessels and maritime traffic.

By August, pirates had hijacked six commercial vessels since April, with some attacks occurring hundreds of kilometers from Somalia’s coastline. Among the vessels seized was the oil products tanker Sibu 1, which was captured approximately 252 kilometers (136 nautical miles) east of al-Mukalla, Yemen.

In September, Puntland authorities reported that pirates had killed five crew members aboard the tanker MT Honour 25 before security forces recovered the vessel. The tanker had been held since April, and authorities said 16 suspected pirates had been detained.

Although international naval patrols and improved maritime security had significantly reduced Somali piracy over the past decade, the latest seizures have renewed concerns over the security of vessels operating off Somalia’s extensive coastline.