The baby boy, injured in the trolleybus explosion in Volgograd, is in coma and his condition is considered to be extremely serious, Russian Health Minister Veronika Skvortsova said on air of the Rossiya 24 (Russia 24) TV channel.

"Three children are among those injured. An infant aged five to seven months is in coma with multiple skull injuries," Skvortsova said.

"It is unknown who he is, it is possible that his parents died," she said.

"The condition of two other children is close to relatively satisfactory, they have minor concussions. It can be said here that everything will be ok," Skvortsova said.