MOMBASA, KENYA— Nine suspected pirates have been arrested on suspicion of trying to hijack a Danish refined oil and chemical carrier in the Indian Ocean on Sunday, NATO's regional anti-piracy force said on Monday.
Pirate attacks stemming from the Horn of Africa, notably Somalia, are at their lowest level since 2006 because of tougher ship security and more Western naval patrols. However, the last few weeks have seen an upsurge.
"This incident is both a positive example of the successes of the international community in deterring piracy and a reminder that we must remain vigilant," said Commodore Henning Amundsen, commander of the Ocean Shield force.
The force said the nationality of the suspects had not been formally determined, but investigations had shown that their craft left Somalia's southeastern coast in late October.
The Torm Kansad, owned by the Danish shipping company Torm A/S, was en route from Sikka in India to Mossel Bay in South Africa when the pirates opened fire as it passed east of Tanzania. An armed security team repelled the attackers before NATO's Esbern Snare rushed to the scene.
NATO also said another vessel, which it did not name, had come under attack three days earlier from a skiff in a similar position, but been repelled by armed security staff.
Suspects detained in similar cases have been handed over for prosecution in Kenya, the Seychelles or Mauritius, although the cases are difficult and lengthy to bring to trial.
The United Nations said last month that there had been 17 attacks originating in Somalia on ships in the first nine months of 2013, compared to 99 in the same period last year.
However, piracy stemming from the impoverished and relatively lawless country may still cost the world economy about $18 billion a year, the World Bank said in April.
Somalia is struggling to rebuild after two decades of civil war and lawlessness, and the pirates have found the seizure of ships for ransom in the Arabian Sea and off East Africa to be a lucrative business.
Meanwhile, attacks on ships in the West African Gulf of Guinea have jumped by a third this year.