With an Argentine submarine missing for five days with 44 people aboard, we recall five of the most deadly submarine disasters over the past few decades.
- Russia's Kursk, 118 dead -
In August 2000, Russia's northern fleet nuclear submarine Kursk catches fire and explodes underwater while conducting war games.
Russian authorities controversially refuse help from British and Norwegian naval vessels, and all 118 sailors on board the submarine are killed.
Most die instantly but some survive for several days -- with a few keeping heart-breaking diaries written in blood to their loved ones -- before suffocating.
It is the Russian navy's worst-ever disaster.
- Chinese navy, all 70 killed -
Seventy Chinese naval officers and crew are killed, apparently suffocated, in an accident on a Ming-class submarine conducting exercises east of the Neichangshan islands in May 2003.
State media says the military was examining human error as a cause, including the mistaken shutting off of crucial exhaust valves, and the possibility of a chemical gas leak.
The government says only there were "mechanical problems".
- Fire on Soviet vessel, 42 die -
In April 1989, a fire following a short circuit breaks out on board a Soviet nuclear submarine, the Komsomolets, as it is in international waters 500 kilometres (310 miles) from Norway.
The crew is not able to put out the fire and quickly brings the vessel to the surface. Dozens dive into the glacial waters to escape, only a few taking to lifeboats.
Some drown but most of the 42 dead are taken down in the submarine when it sinks. Twenty-seven people survive.
- Gas on a Russian sub kills 20 -
The fire extinguishing system of a Russian nuclear Nerpa submarine is accidentally activated in November 2008, releasing a poisonous gas that kills 20 people, including three naval officers and 17 civilians.
Another 21 people are injured in the accident, which happens as the high-speed attack submarine is being tested in the Sea of Japan.
- Indian explosion, all 18 die -
The fully armed Russian-built Indian INS Sindhurakshak submarine explodes in a fireball in Mumbai harbour shortly after midnight in August 2013 and sinks.
All 18 sailors onboard are killed. The fierce temperatures generated in the fire ignited some of the weapons on board, such as cruise missiles and torpedoes.
The disaster came soon after the vessel had been returned by Russia following a major refit.