Donald Trump told to 'grow up' - but why?

Image source, AFP/Getty Images

It's almost time for Donald Trump to officially become the president of the US.

However, he has found himself being criticised this week for things he has said on social media.

Video caption, Why has Donald Trump been told to 'grow up'?

But what did he say and why are people cross about it?

What has Donald Trump done?

Since winning the election, Donald Trump has often used social media to tell people what he thinks.

One of the things that Donald Trump has tweeted about recently is to do with how he won the election.

He has disagreed with something that his own American spies have said.

The spies have said that Russia got involved with the US election to try to help Trump win.

They say Russia hacked into Hillary Clinton's team's emails and released embarrassing information about her.

However, Donald Trump has said on Twitter that he does not believe that the American spies have got it right.

What have people said?

Many people don't think that the way that Donald Trump has been sharing his opinions on social media is appropriate for a man who is about to become president.

Recently, his opponents have criticised him for not supporting the work of his own US spies.

The current vice-president of the US called Joe Biden - who is second in command to President Barack Obama - said in an interview that he needs to "grow up".

Image source, European Photopress Agency

Image caption, Joe Biden can be seen here standing to the right of the current president Barack Obama

It is unusual for a US president to speak out in this way disagreeing with what his own spies are saying.

However, those who support him say it is a good thing that he is doing things differently to politicians in the past.