Authorities are investigating whether the explosion in Chelsea, which injured 29 people last night, was carried out by the same person who blew up a series of pipe bombs in Seaside Park, NJ. Law enforcement sources told CNN that both devices were set off with cell phones, and they are trying to determine whether they may have been triggered by the same attacker.

This is one of several leads being pursued this afternoon: the FBI are evaluating claims that a person took credit for the attack on a (now-deleted) Tumblr page. As Daily Beast reported, prominent members of the alt-right community have been circulating the unlikely manifesto, which credits liberals and the LGBT community itself for the attack. "I can't discount it altogether but I would be very surprised if it was the guy," a law-enforcement source told them.

The Post also reports that a man made a threatening call to 911 right after the attack, saying, "I’m looking at the explosion down the block. There will be more." A hand-written letter, a portion of which is in Arabic, was also reportedly found inside a plastic bag that held the second device.

#BREAKING @FBI/NYPD probing suspicious Uber passenger last night in #Chelsea. Driver reported incident today. Investigation @ 39/Madison. — Anthony DiLorenzo (@ADiLorenzoTV) September 18, 2016

At a press conference early this afternoon, Mayor de Blasio stressed that people be patient and not jump to any conclusions: "The investigatory agencies continue to look to see if there is any specific connection to the incident in New Jersey," he said. "At this point we do not have any specific evidence of a connection, but that will continue to be considered. So we’re not taking any options off the table. I want to be very clear about that. All possible theories of what’s happened here and how it connects will be looked at, but we have no specific evidence at this point in time."

As for Governor Cuomo's declaration that the explosion was "an act of terrorism," de Blasio didn't quite use the same language:

Now this was a very serious incident. It’s going to take a lot of careful investigation to get to the facts and get to the truth. One of the things we’re going to say to you today is we’re going to be very careful and patient to get to the full truth here. We are not going to jump to conclusions. We are not going to offer you easy answers. We are going to make sure we have all the facts. We know there was a bombing. That much we do know. We know it was a very serious incident, but we have a lot more work to do, to be able to say what kind of motivation was behind this. Was it a political motivation, a personal motivation, what was it? We do not know that yet. That work must go on. And we’re going to give you regular updates as we get more information.

@NYPDONeill calls bombing a "violent criminal act." Neither he nor @BilldeBlasio used the word terror or terrorism. — J. David Goodman (@jdavidgoodman) September 18, 2016

.@BilldeBlasio won't comment on Cuomo's characterization as terrorism but says "“Let the law enforcement experts draw the conclusions.” — Erin Durkin (@erinmdurkin) September 18, 2016

But politicians are already seizing upon the language: Hillary Clinton condemned the "apparent terrorist attacks in Minnesota, New Jersey and New York."

Hillary Clinton Statement on Apparent Terrorist Attacks pic.twitter.com/EOGHVlp57O — Zeke Miller (@ZekeJMiller) September 18, 2016

For his part, Donald Trump offered his "condolences" in a tweet to the victims of the Chelsea explosion, even though nobody died. Clinton also criticized Trump for telling supporters "a bomb went off in New York" an hour after the explosion: "I think it’s also wiser to wait until you have information before making conclusions, because we are just in the beginning stages of trying to determine what happened."