Manchester United [Images] manager Alex Ferguson has warned that he will not tolerate criticism of players from within Old Trafford being made public.

Ferguson is understood to have been behind the decision to pull the plug on an interview this week in which club captain Roy Keane hit out at his team mates on the club's television station.

"You don't criticise any of the Manchester United players outside the doors. I've never done. I won't," Ferguson told reporters on Friday.

The pressure on United and Ferguson has intensified in recent weeks following a patchy start to the season and after damaging defeats to Middlesbrough and Lille, the manager reminded all his staff of the need to toe the line.

"It's not any tougher than any other week when you have bad results. We have had them in periods over the years.

"You have to deal with it. Of course there is criticism, criticism coming from all directions and what you have to do as manager of our club is to make sure the criticism remains inside your doors.

"I'm unremitting in that respect, unequivocal, the stance is there and it won't change."

Ferguson also said he is prepared to withdraw his players from England's [Images] squad to play Argentina this month.

United's Wayne Rooney [Images], Rio Ferdinand, Kieran Richardson and Alan Smith are likely to be named in Sven-Goran Eriksson's squad for the friendly in Geneva next Saturday.

With United's squad decimated by injuries, however, Ferguson has warned he may not allow the quartet to go, jeopardising his side's chances of progressing in Europe and closing the gap on English Premier League leaders Chelsea.

"I've never had problems with competitive games but I'll not risk my players in a friendly," he told the Manchester United magazine.

"I do not like friendly internationals. England have one this month and you can bet that Chelsea and Arsenal [Images] will be pulling their players out.

"And if I have the injury problems I have at the moment, I will be too."

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