Sergio Aguero stretchered off in tears playing for Argentina vs Ecuador
Manchester City star Sergio Aguero suffered a hamstring injury while playing for Argentina in the 2-0 World Cup qualifying defeat by Ecuador.
The 27-year-old is set to have a scan and looks likely to miss Argentina's game against Paraguay next week.
Aguero had only just returned to fitness after a knee injury earlier in the season.
A statement on the City website said: "The striker pulled up holding his left hamstring while chasing a long ball downfield. He was stretchered off in tears and replaced by former Blue Carlos Tevez."
Argentina boss Gerardo Martino said later: "He had been carrying a knock with his club, during the week we took good care of him. He was moving around the pitch well, but unfortunately he felt some discomfort and we are going to lose him.
"I haven't spoken to the doctor but I can confirm the injury is not the same as the one he had been carrying with his club."
Nicolas Otamendi, who also started the game, added: "He had been having a great time and was playing well."