Charles Leclerc is contributing to the tension at Ferrari.
Marko thinks Ferrari is also to blame.
"Vettel was ahead (at Sochi), so Leclerc complained and then the engineer said 'Don't worry, we'll fix it with the pitstop'," Marko told Servus TV.
"What that means is 'we'll manipulate the pitstop'. That's against fairness and against sport," he charged.
"The whole situation is difficult enough for Ferrari, so why worsen it by consciously playing the drivers against one another?"
But Marko said it is not new territory for the Maranello team.
"Ferrari loves these games, although most of the time it doesn't turn out well. But that's just Ferrari.
"It's a different culture," he added.
Marko also thinks Leclerc brought on Sebastian Vettel's refusal to comply with team orders at Sochi.
"If Vettel didn't stick to the rule at Sochi, then Leclerc didn't stick to the rule in Monza," he said.
"He was supposed to give Vettel a slipstream in qualifying. He's definitely playing his part in the tension."body check tags ::