Did the LDS believe that Christians are doomed to hell? While perusing the Vatican's official website, I stumbled upon this: 


  THOUGHTS FROM THE DIALOGUE CENTRE IN ÅRHUS, DENMARK
  
  "... The Church of Jesus Christ of Latter Day Saints (Mormons) used to
  teach with some vehemence that Christians were doomed to hell."



Source: Spirituality in East and West, Easter 2000 (No. 13), from Dialog Center International, 46 Katrinebergvej, DK-8200 Aarhus, Denmark. info@dci.dk Retrieved from vatican.va


This notice was apparently delivered by the Pontifical Council for Culture and published in a semi-annual journal. 

Does the Catholic Church support this statement? From what teaching/teachings do they suppose this statement is founded? 



UPDATE - Oct 9, 2014
A lot of good research has been contributed by all of the answers below in response to this question, I wish to thank all those that took the time to investigate the statement above.  

To summarize the ultimate conclusion: it has been concluded that the contributor to vatican.va in this instance was in error in three way profound ways:


He posted materials on the official vatican site that did not support or represent the official stance of the Catholic Church.
He improperly cited the source and author of the statement - who was not even a Catholic. (The message is similar, but the wording is actually taken from a different source)
He misrepresented the philosophy of the LDS Church, as they have a very different interpretation of "hell" compared to most Christian denominations, and use the word mostly to describe a feeling of eternal regret. Sometimes, they use the word to refer to either the spirit prison, or outer darkness, which are two very distinct places, the latter being inhabited only by Satan and the sons of perdition.


The LDS definition of Hell:


  Latter-day revelations speak of hell in at least two ways. First, it
  is another name for spirit prison, a temporary place in the postmortal
  world for those who died without a knowledge of the truth or those who
  were disobedient in mortality. Second, it is the permanent location of
  Satan and his followers and the sons of perdition*, who are not
  redeemed by the Atonement of Jesus Christ. [outer darkness]


*Sons of Perdition: Those who actively serve Satan and utterly reject God.
Update 2 Wednesday, October 08, 2014: The error in an article by an author of an article on the Vatican website CANNOT be attributable to the Catholic Church.

Summary of the findings so far

Is there evidence that The Church of Jesus Christ of Latter-day Saints (the LDS Church or, informally, the Mormon Church) officially teaches or has taught in the past


  "... The Church of Jesus Christ of Latter Day Saints (Mormons) used to
  teach with some vehemence that Christians were doomed to hell."


No there isn't.

What appears to be the primary source of the above quote that has gone on to be quoted by vatican.va?

It appears to be this book The Protestant Revolution: From Martin Luther to Martin Luther King Jr. By William G. Naphy.

What did this article - Forside  Publikationer  Læs Spirituality  No. 13  I said, you are gods - actually say? It said


  Previously, Mormons were taught, and said in their witnessing, that
  Christians are going to hell.


Is this accurate?

There seems to be some truth to it as Bruce R. McConkie went on to write a book that stated


  "Believers in the doctrines of modern Christendom will reap damnation
  to their souls (Morm. 8; Moro. 8)" (Mormon Doctrine, 1966, Bruce R.
  McConkie, 177)


What appears to be the error of vatican.va?

They have attributed


  The Church of Jesus Christ of Latter Day Saints (Mormons) used to
  teach with some vehemence that Christians were doomed to hell.


to: Spirituality in East and West, Easter 2000 (No. 13), from Dialog Center International, 46 Katrinebergvej, DK-8200 Aarhus, Denmark. info@dci.dk

And that's an error as that's not what Spirituality in East and West's article said as shown above.

What is the answer to OP's


  Does the Catholic Church support this statement? From what
  teaching/teachings do they suppose this statement is founded? Better: Can the Catholic Church ...


From what has been presented above, she can't. Please note that vatican.va is NOT the Catholic Church. The error belongs in the first place to the author of THOUGHTS FROM THE DIALOGUE CENTRE IN ÅRHUS, DENMARK.

What is the OP to do now?

Suggest OP contact vatican.va directly.

vatican.va as any human website can and even recently made a mistake and corrected it. cf. Scalfari interview taken down from the Vatican website.

What follows below is what helped in shaping the answer above.



For these kind of questions, my response is better contact the author of the document directly


  "I suppose you'd have to ask the author of the Spirituality in East
  and West article." –  @MattGutting


One may wish to start here: Vatican emails and the contact of relevance appears to be: Pontifical Council for Culture: cultura@cultr.va. That to me would be the best way to answer/clarify Does the Catholic Church support this statement? from what official LDS resource/resources do they suppose this statement is founded? 



From ShemSeger's answer, it appears that opposing views were published in in Volume No. 13 of the periodical journal, "Spirituality in East and West".

Thus perhaps the question is asking why has the Vatican website posted only one of the views. That is a question only the Vatican website can answer.



This is what my research has uncovered


  Joseph heard so many competing versions of truth that he decided to turn to God for answers.
  
  After careful study, he still felt confused. He later wrote, "So
  great were the confusion and strife among the different denominations,
  that it was impossible for a person young as I was [ … ] to come to
  any certain conclusion who was right and who was wrong [ … ] In the
  midst of this war of words and tumult of opinions, I often said to
  myself: What is to be done? Who of all these parties are right; or,
  are they all wrong together? If any one of them be right, which is it,
  and how shall I know it?" (Joseph Smith-History 1:8, 10).
  
  Joseph turned to the Bible for guidance. [...] He decided to pray
  about what he should do, with simple faith that God would hear and
  answer him.
  
  Source: Joseph Smith, History &amp; Belief of the Mormon Prophet | Mormon.org


In response to a humble prayer, God called Joseph to re-establish the Church of Jesus Christ.


  19 I was answered that I must join none of them, for they were all
  wrong; and the Personage who addressed me said that all their creeds
  were an abomination in his sight; that those professors were all
  corrupt; that: “they draw near to me with their lips, but their
  hearts are far from me, they teach for doctrines the commandments of
  men, having a form of godliness, but they deny the power thereof.” -
  (Joseph Smith-History 1:19).


It does appear that a certain Bruce R. McConkie went on to write a book that stated


  
  "Believers in the doctrines of modern Christendom will reap damnation to their souls (Morm. 8; Moro. 8)" (Mormon Doctrine, 1966,
  Bruce R. McConkie, 177).
  
  
  Source: Mormon Stumpers | Catholic Answers.


From the comments to the answers to the OP, some have stated that this does not constitute official teaching of The Church of Jesus Christ of Latter Day Saints (Mormons).



Perhaps a book such as The Protestant Revolution: From Martin Luther to Martin Luther King Jr. | William G. Naphyan  - which in turn references A Closer Look at the Book of Mormon (2001) | Tal Davis - was the source of what the OP stumbled upon on Vatican's official website. 




cf. Online Full Text of Mormon Doctrine . (Find: "damnation to their souls")


For further research please see this Google search.



Update Wednesday, October 08, 2014

I contacted a Mr. Tal Davis as follows (sans links):


  Mr. Davis. Please take a look at:   
  
  The Protestant Revolution: From
  Martin Luther to Martin Luther King Jr. | William G. Naphyan (scroll up)   
  
  That books (sic) references  a Tal Davis’  A Closer Look at the Book of Mormon (2001) as the source of the quote. Not sure whether you are associated with the 2001 item.


This was his response:


  In 1992 I wrote an article that was adapted for a pamphlet titled "A
  Closer look at the Book Of Mormon- Is It Another Testament of Jesus
  Christ?" You can see the text of that article, with more current
  statistics, on the MarketFaith website at The Book of Mormon: Is It
  “Another Testament of Jesus Christ?”  If you read it you will see that
  the quote is not there.  I do not know why it was attributed to me
  unless the original magazine article had the quote in an introduction
  written by the editor (I would not have spelled Latter-day Saints as
  Latter Day Saints). The magazine ("Church Training") went [out] of
  publication years ago and I don't have a copy of the issue so I cannot
  verify that theory.     
  
  In any case, I know that the LDS does not
  teach that all Christians (nonMormons) are doomed to hell (just to
  Spirit Prison and the Terrestrial or Telestial Kingdoms). However,
  Mormon leaders on numerous occasions have clearly stated that all
  Christian denominations are apostate. In fact, until 1990 the LDS
  temple dramas portrayed Protestant ministers as followers of Satan.