“My sincere apologies, I apologised to the families last night, but today I want to do it publicly.”
Mr Basterra said he felt “a lot of shame” over his mistake.
He said: “I would never make fun of those who deserve all my admiration and respect.
“It was a mistake to put on that shirt which I have used many times without giving it any particular meaning.”
“People who know me know that I would never do something like this on purpose to insult the national symbols.”
To make his position clear, Mr Basterra resorted to capital letters in his post: “The mistake I made does not take away THE PRIDE OF BEING ARGENTINE, I CARRY IT DEEP IN MY HEART”.
The incident comes at a time of heightened tensions over the Falklands in Argentina.
Buenos Aires has said its mission to retake islands “doesn’t only concern Argentina, but also the entire region” as the nation’s government reinstate the task to retake islands as “state policy”.
Argentina’s Malvinas Secretary Daniel Filmus said: “The Malvinas cause doesn’t only concern Argentina, but also the entire region.”
“This base in no way has a defensive sense, since Argentina has reiterated that the only way to recover the exercise of sovereignty is through peace and dialogue.
“The main objective of the military presence is to ensure British access and control of Antarctica, the bi-oceanic corridor between the Atlantic and the Pacific, and to ensure that the United Kingdom can continue to exploit the natural resources of that entire region.
“The Argentine Foreign Ministry strongly condemned Boris Johnson’s decision to maintain a military presence in the Islands.”
(Additional reporting by Maria Ortega)