Facebook is to add a "dislike" button to its social network, founder Mark Zuckerberg has said.
In a Q & A session held at Facebook's headquarters in Menlo Park, California, the 31-year-old said the button would be a way for people to express empathy.
He said Facebook - which recently cracked the 1 billion daily users mark - was "very close" to having it ready for user testing.
A "dislike" button has been constantly requested by some users since the introduction of the now-ubiquitous "like" button in 2009.
Facebook has previously resisted the idea, saying it did not want to open the doors for harassment or bullying.
"People have asked about the 'dislike' button for many years," Mr Zuckerberg told the audience on Tuesday.
"Probably hundreds of people have asked about this, and today is a special day because today is the day that I actually get to say we are working on it, and are very close to shipping a test of it."
However he went on to say he did not want it to be a mechanism with which people could "down vote" others' posts.
Instead, it will be for times when clicking "like" on "sad" posts felt insensitive.
Some Twitter users were circumspect.
I'm sure the "Dislike" button Facebook is building will be used only in appropriate ways and not to bully teens— patrick (@pattymo) September 15, 2015
But others simply found the announcement amusing.
Facebook says they'll release a dislike button when they figure out how it'll express sympathy. This is what it sounds like when thumbs cry.— @midnight (@midnight) September 15, 2015
Facebook risks becoming a more fractious site like Reddit - something it will want to avoid, given Reddit's recent troubles.
However, Professor Andrea Forte, an expert in social and participatory media at Drexel University in Philadelphia, told the BBC users will not suddenly turn on each other's posts.
In an email, she wrote: "They may use a dislike button to express some negative emotions (like frustration with ads popping up in their feeds) but I doubt it will cause them to start wantonly disliking pictures of their friends' babies, dogs, cats and cooking experiments."
Robinson Meyer, a technology writer for The Atlantic, asked if maybe a heart would be a better symbol than a thumbs down.
"In various situations, ♥ can represent joy, anguish, empathy, and adoration. Much like the word "friend," in other words, it is already wonderfully multivalent - an ambiguity that Facebook can exploit, as it becomes a messenger of thought and feeling for more than 1 billion people every day."