I don't know if it was Seagal himself or someone working his Twitter feed (most likely) but this is nothing more than just an attempt to get fans excited for something that has very little to no chance of happening IMO.
Above The Law came out almost 30 years ago and it wasn't even Seagal's most succesful movie (Under Siege is), even though it's probably my favorite movie of his, or among the top 3, it was just an action movie of its time. There is nothing that unique about the concept or the story, nothing that would have any value in today's market.
Even though Under Siege was basically another Die Hard type movie, at least there's an inkling of hope of US3 happening (truthfully less than 2%, it won't happen either).
I doubt Seagal and his team have any sort of relationship with Warner Brothers, and I doubt WB would be interested in working with them on a sequel to a movie most people don't even remember.
I think Seagal and/or his team are getting desperate. Truthfully his major movie career ended 15 years ago and even his days of cashing in million dollar checks from DTV movies are gone. He's now doing these one day cameos for quick cash in ultra low budget movies, and soon they will stop as well and he will go the way of Don "The Dragon" Wilson and Jeff Speakman.
He's now trying to kickstart his movie career back on track with Attrition but they seem to have problems getting funding. 5-10 years ago they could have greenlit it just like that.
He has even said "maybe" when asked about doing Expendables. something he flat out said he would not be interested in a few years ago.
Well there won't be another Expendables most likely, and even if there will be I doubt Sly and Avi would even ask Seagal since he already turned them down numerous times.
Beggars can't be choosers.
Look at Van Damme's career, he was pretty much on the same level with Seagal during their DTV hayday. He did EX2, it gave a boost to his career. He did two of the Universal Soldier DTV sequels that were well liked by fans, he did JCVD that proved he can actually act. He's now shooting the second Kickboxer movie, first of which hasn't been released yet and his Amazon pilot Jean-Claude Van Johnson will be released soon.
Even Dolph Lundgren who never achieved the career of Steven Seagal at his height, has been appearing in high profile stuff, either doing cameos in big A-list projects, or starring in high profile DTV movies like Kindergarten Cop 2.
The difference between Van Damme and Lundgren and Seagal? They actually challenged themselves, they took parts that Seagal must have deemed "beneath him", they kept in shape, they played the game.
Seagal must now realize he screwed it up, but I'm afraid it's little too late now.