This morning at least nine Russian plain clothes security agents - wearing shiny dark suits and sunglasses - were stationed at positions close to the front gates of the Australian training complex, which is set in a leafy park, popular with young mums and their kids.

Until now, a security cordon of just two - plus the usual uniformed security guards - have been seen watching the compound taken over by Australia.

The Australian media centre and training ground, literally just a few metres from the players' accommodation, has always been under tight security with metal detectors and a legion of guards.

But the furious reaction to Robbie Kruse's performance against Denmark appears to have prompted the massive increase in security at the compound opposite.

Among the insults and fury at his performance last night were some random potential death threats, which although probably intended for shock value, may have provoked the reaction from Russian authorities.

Football Federation Australia said they were unaware of the increased protection but added: "We don't comment on security matters at any time for obvious reasons."

But Socceroo defender Mark Miligan said no-one was focusing on comments on social media.

"As we all do, Robbie probably doesn't read into those things too much," said Milligan after training today.

"It's unfortunate that some people forget that at the end of the day, we're doing our very, very best to entertain and represent our families and our countries.

"It's an unfortunate situation and we tend to just stay away from it. It's disappointing.

"People are entitled to their opinions but you don't have to take things that far."

He added: "It's much more important what we think of each other than what everybody else thinks of us.

"When we're out on the field, we're the only ones that can help us and we have a great belief in each other."

But he paid tribute to the fans that have followed the Socceroos to Russia and made both games so far feel like home games for the green and gold.

"They've been amazing," he said. "It makes such a difference. 

"It's much easier to come back into matches when you have that sort of support and they have been fantastic."