Somali pirates have hijacked more than 80 ships in the past two years. Tuesday's hijackings brought the number of attacks in the Gulf of Aden and off Somalia to 214 this year, with 47 vessels hijacked.
Some piracy-related events this year:
Dec. 28 _ Pirates seize chemical tanker in Gulf of Aden and ship in Indian Ocean.
Dec. 2 _ The Dutch navy captures 13 Somali pirates and seizes a haul of weapons off the coast of Oman after the pirates attacked a merchant ship.
Nov. 17 _ Pirates free a Spanish trawler and its 36-member crew after a $3.3 million ransom is delivered as a Spanish warship looks on.
Oct. 29 _ A British couple sailing a yacht off Somalia say they have been seized by pirates. They still have not been freed.
Sept. 7 _ A dispute erupts between authorities in Somalia and the Seychelles after the island nation released 23 suspected Somali pirates in what appeared to be a trade for hostages from the Seychelles.
Aug. 26 _ Somali pirates holding a hijacked ship fire at a U.S. Navy helicopter as it makes a surveillance flight over the vessel, the first such attack by pirates on an American military aircraft.
Aug. 13 _ Using machetes and guns, Egyptian fishermen held hostage for four months regain control of their vessels from pirates.
June 9 _ The U.S. Navy warns that pirates from Somalia have expanded their areas of operation far from the coast and into the Red Sea.
April 25 _ Italian cruise ship fends off pirate attack with gunfire off Somalia's coast.
April 15 _ French forces capture a suspected Somali pirate mother ship.
April 13-14 _ Pirates capture four ships and take more than 60 crew members hostage in a brazen hijacking spree.
April 13 _ Navy SEAL snipers shoot three Somali pirates in a lifeboat and rescue Richard Phillips, the hostage captain of the U.S.-flagged Maersk Alabama after five days at sea.
April 10 _ Pirate recapture Phillips after he tries to swim for freedom.
April 8 _ The unarmed crew of the Maersk Alabama wrests control of the U.S.-flagged cargo ship from Somali pirates and sends them fleeing to a lifeboat with the captain as hostage.
March 26 _ Pirates armed with machine guns hijack a Norwegian chemical tanker less than 24 hours after a smaller Greek-owned vessel is seized in the same area.
March 5 _ A Ukrainian cargo ship carrying tanks and other heavy weapons is freed and sails for Kenya under U.S. military escort after a $3.2 million ransom is air-dropped more than four months into the ship's captivity.
Jan. 29 _ Somali pirates hijack a German tanker loaded with liquefied petroleum gas off the Horn of Africa.
Jan. 10 _ Five of the pirates who hijacked a Saudi supertanker drown with their share of a $3 million ransom, the day after the ship _ the Sirius Star _ was freed.
Jan. 8 _ The U.S. announces a new international naval force under American command will patrol to confront escalating attacks by Somali pirates after more than 100 ships came under siege in the past year.