Sri Lanka's Ministry of Foreign Affairs released a statement on the hijack, stating that is "taking action to verify the alleged incident, and initial enquiries have revealed that while the vessel involved is not registered under a Sri Lankan flag, it has an eight-member Sri Lankan crew".
The ship had been carrying fuel from Djibouti to Somalia's capital, Mogadishu, when it was approached by men in two skiffs.
There are thought to be eight people on board the Sri Lankan boat, alongside 12,000 tonnes of cargo.
Somali pirates tend to be well armed with automatic weapons and Rocket Propelled Grenades (RPG) and sometimes use skiffs launched from mother vessels, which may be hijacked fishing vessels or dhows, to conduct attacks far from the Somali coast.
The United Nations warned in October that the situation was fragile and that Somali pirates "possess the intent and capability to resume attacks".
The EU Naval Force has confirmed that Aris 13 and its crew are being held captive.
"The local authorities up there confirm pirates have a ship they are holding, and are holding the crew against their will", Steed said in an interview on Twitter.
Struggling to push his small fishing boat out to sea, Hassan Yasin grumbles over what he and other coastal Somalis call a threat to their way of life: harassment by illegal fishermen and attacks by large foreign trawlers.
Reuters has quoted a regional police official saying "security forces have been sent to free the Aris 13". There was a deployment of global naval forces and an adoption of safety measures such as avoiding high risk areas, having armed guards on board and installing barb wire on exteriors of ships.
This is the first hijacking in the region for five years, and maritime experts have accused ship owners of becoming complacent after a long period of calm.
Chief executive of Sailors' Society-a charity that aids seafarers-Stuart Rivers said that it was "distressing" to hear that pirates were active again off the Somali coast. "The ship changed course quite soon after that report and is now anchored", added she.
Illegal fishing in Somali waters, often by ships from Southeast Asia, feeds resentment among locals, who have seen outsiders looting their resources, Steed said.
An official based in the Middle East with knowledge of the incident said that no ransom demand had been made.
"This attack reinforces the need for vessels to follow shipping industry best management practices within the specified high risk area", the organisation said.
At the height of the hijacking crisis in 2010-11, Somali pirates were attacking dozens of ships each month and receiving multi-million-dollar ransoms to release hijacked vessels and their crews.
The U.N. report concluded: "The ultimate solution to the problem of piracy off the coast of Somalia lies in a stable and secure future for Somalia".
42 dead in air attack on refugee boat near Yemen
Some 85 Emirati soldiers have been killed since the beginning of Saudi Arabia's military campaign against Yemen two years ago. A sailor who had been operating the boat, Ibrahim Ali Zeyad, said 80 refugees had been rescued after the incident.