CAMP LEMONNIER, Djibouti — Commercial ships must once again shore up their defenses against forced boardings at sea, United States Defense Department officials said on Sunday, warning that Somali pirates are returning to waters off East Africa after five years of calm.
Defense Secretary Jim Mattis said that while he was not calling for a response yet from the United States Navy, a half-dozen pirate attacks on commercial ships off the coast of Somalia in the past eight weeks meant that civilian mariners and shipping companies must again be on high alert.
American military commanders at the Pentagon’s sole semipermanent base in Africa, Camp Lemonnier in neighboring Djibouti, have been monitoring the attacks.
Gen. Thomas D. Waldhauser, the head of the United States Africa Command, said drought and famine in Somalia are probably behind the recent spike in attacks, in which pirates have boarded commercial ships and seized food and oil.
Most of these attacks, including a hijacked oil tanker last month, are believed to have been carried out by pirates from central Somalia or from Puntland, a semiautonomous region in northeastern Somalia.
General Waldhauser said the military was urging civilian shipping lines to bolster their security. Military officials said some commercial shipping companies had let go some of the security guards hired to protect their ships after the decline in attacks.
About one-third of the world’s commercial ships travel near Djibouti, through the Gulf of Aden and toward the Mediterranean, and the return of attacks may mean another coordinated international effort to fight piracy, officials said. During the height of the last round of attacks, a coalition of foreign navies increased patrols along Somalia’s coastline.
“We’re not ready to say that there’s a trend,” General Waldhauser said. “But we’ll continue to watch it.”
The general’s comments came during a news conference with Mr. Mattis at Camp Lemonnier, the American base established after the Sept. 11 attacks, when the military was looking for a foothold in Africa from which to monitor Qaeda groups on the continent and in the Middle East.
Djibouti, in the Horn of Africa, is just across the Gulf of Aden from Yemen, and the American outpost here has been used as an operational base for missions including surveillance of Islamic extremist organizations like the Shabab in East Africa and helping the coalition led by Saudi Arabia in its fight against Iranian-backed Houthis in Yemen.
Mr. Mattis was in Djibouti as part of a weeklong tour of the Middle East. He met with the country’s president, Ismail Omar Guelleh, and its minister of defense, Ali Hassan Bahdon.
The return of pirate attacks off Somalia’s coast comes as the country’s fledgling government, supported by the United Nations, is trying to battle the Shabab. Most of the fighting against the extremist group has been done by a regional force backed by the African Union, but some of the countries that have sent troops say they are planning to depart starting in 2018.
That has left the United States military scrambling to try to prepare Somalia’s armed forces to take over the fight. But the country’s poorly trained and ill-equipped armed forces must make substantial progress before they will be able to replace the regional force, which numbers 22,000 troops.
At the moment, Somalia’s armed forces has 12,000 fighters, American military commanders said
