“It’s tough, it’s not the time for analysis,” he said. “In the dressing room I thought that this is the end for me with the national team, it’s not for me.
“That’s the way I feel right now, it’s a huge sadness once again and I missed the penalty that was so important.
“I tried so hard to be champion with Argentina. But it didn’t happen. I couldn’t do it.”
The decision by the 29-year-old, who surpassed Gabriel Batistuta as his country’s highest goalscorer last week, came as a shock to his team mates, who said they hoped his decision was not irrevocable.
Sergio Aguero, Messi’s best friend on the team, said he had never seen the mood in the dressing room so low while goalkeeper Sergio Romero suggested he might rethink his decision.
“I think Leo spoke in the heat of the moment because we missed that great chance,” said Romero.
Messi, widely held to be the greatest player of his generation, has won every trophy possible at club level with Barcelona, though his only titles with Argentina were the Under-20 World Cup and the 2008 Olympics.
He has played in three Copa America finals in 2007, 2015 and 2016 and the 2014 World Cup final, and was on the losing side every time. Argentina failed to score in all four matches.