The Republican candidate says the newspaper "has become a laughingstock rag"
Donald Trump has said his lawyers want to sue The New York Times newspaper "so badly" for "irresponsible intent".
In a tweet, the Republican presidential candidate said he has told his lawyers not to sue "for now", but threatened that they are "watching".
My lawyers want to sue the failing @nytimes so badly for irresponsible intent. I said no (for now), but they are watching. Really disgusting— Donald J. Trump (@realDonaldTrump) September 17, 2016
The comments followed an earlier tweet in which Mr Trump suggested the paper had become a "laughingstock rag".
The failing @nytimes has gone nuts that Crooked Hillary is doing so badly. They are willing to say anything, has become a laughingstock rag!— Donald J. Trump (@realDonaldTrump) September 17, 2016
It is uncertain what prompted the comments, although Mr Trump has long been critical of the newspaper's coverage of him and his campaign.
In their latest investigation into Mr Trump and his businesses, published yesterday, The NY Times reports that the Trump empire was "built on inside connections and $885 million in tax breaks".
The editorial board of the paper has also been extremely critical of Mr Trump. On Friday they described his eventual admission that President Obama was born in the US as "another bizarre moment in the absurdist presidential campaign of Donald Trump".
In the US, a person suing for libel has to prove a publication published incorrect information with "actual malice".
In February, Mr Trump claimed he will 'open up' libel laws if elected, saying: "So when The New York Times writes a hit piece which is a total disgrace or when The Washington Post, which is there for other reasons, writes a hit piece, we can sue them and win money instead of having no chance of winning because they're totally protected."
Earlier this week, a New York Times & CBS poll of likely voters showed Hillary Clinton with a narrow lead over Mr Trump, with only two points separating the two candidates (at 46% to 44%).