RACHEL MARTIN, HOST:
Police in New York City are investigating a powerful blast that shook the Chelsea neighborhood of Manhattan last night. Authorities say it was a homemade bomb and that it was an intentional act, but not - so far, anyway - linked to terrorism. Here's what New York City Mayor Bill de Blasio said last night.
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MAYOR BILL DE BLASIO: There is no evidence at this point of a terror connection to this incident. This is preliminary information. It's something we will be investigating very carefully, but there is no evidence at this point of a terror connection.
MARTIN: NPR's Dina Temple-Raston has been following this story, and she's joining us now from New York. Good morning, Dina.
DINA TEMPLE-RASTON, BYLINE: Good morning.
MARTIN: What are you learning?
TEMPLE-RASTON: Well, the blast happened around 8:30 last night around West 23rd, between 6th and 7th Avenues, near the Flatiron Building. And that's in the middle of this upscale neighborhood here called Chelsea. And our sources confirm that investigators believe a homemade bomb was placed in a dumpster in an alley and exploded there. And it was pretty powerful and sent metal and flying glass in all directions, and 29 people were injured. And none of the injuries, we understand, are life-threatening.
MARTIN: Police found a second device that didn't detonate. It was about four blocks away, right?
TEMPLE-RASTON: Right. And it's unclear if the two devices are related. They're investigating that. But the second device looks a lot like the kind of homemade bomb that was used during the Boston Marathon attack. You basically put some sort of explosive - in the Boston case, they put gunpowder from fireworks - into a pressure cooker with nails and ball bearings, and you hook that up to a detonator and a timer or a cell phone, and it's wired to deliver a spark. And then it detonates and the pressure makes it more powerful. So it isn't very complicated, and instructions for this kind of device have been on the internet for years.
MARTIN: But the Boston Marathon bombers were clearly terrorists attacking the race, trying to make a political statement with that. Officials in New York say they're not sure this is terrorism. It's still up in the air. What conclusive evidence would they need? What are they looking for?
TEMPLE-RASTON: Well, they say that they haven't been able to find any terrorist connection - say, social media or some sort of link to ISIS or al-Qaida. And it's meaningful that they've said this so quickly because typically they don't rule anything out early in an investigation. But in this case, they very pointedly downplayed terrorism, and we're trying to run down why. Clearly they have some sort of evidence that's taken them in that direction. For example, was there a note or have they pulled a fingerprint that gives them some indication of who did this? Again, we don't know exactly what it is they have, but clearly investigators have something on which to base their initial conclusion that this doesn't have a link to terrorism.
MARTIN: And just briefly, Dina, you live in New York. Have you been out this morning? Is there a big police presence?
TEMPLE-RASTON: There isn't a huge police presence. They have closed the area between 14th Street and 32nd, between 5th and 8th, which is a huge swath of downtown. They're looking for evidence. They're looking for additional devices. So that part of the city is on high alert, but the rest of the city seems to be getting back to normal. I didn't see anything unusual in terms of security, and that typically happens when we have one of these kinds of attacks. The last time we had one was in 2010. There was this car that was wired to detonate in Times Square, and it turned out to be just a big smoke bomb. And we haven't had anything since then. And this doesn't feel like that.
MARTIN: NPR's Dina Temple-Raston. Thank you so much, Dina.
TEMPLE-RASTON: You're welcome. Transcript provided by NPR, Copyright NPR.