The men behind last month's deadly attacks in Brussels had intended to strike Paris instead — but shifted their target as Belgian authorities closed in on them, Belgian investigators say.

Teri Schultz tells NPR's Newscast unit that this information emerged after authorities arrested and interrogated key suspects.

Here's more from Teri:

"Authorities say they have many clues now that show the intention of the terrorist group was to attack again in France. Prosecutors say the network was 'surprised by the speed of the investigation,' so it switched the target to Brussels."

No further details were immediately available.

The attacks at the airport and a metro station killed 35 people (including three attackers) and wounded more than 300. They happened just four days after authorities arrested Salah Abdeslam, a lead suspect in last November's attacks in Paris.

As The Associated Press reports, "Sunday's statement provides confirmation of what many have suspected: the series of raids and arrests in the week leading up to the Brussels attacks — including the capture of key Paris attacks fugitive Salah Abdeslam — pushed the killers to action."

This comes a day after Belgian federal prosecutors said Paris attack suspect Mohamed Abrini, who was arrested Friday, admitted that he is the suspect known as the "man in the hat" seen in surveillance footage from the Brussels airport with the two suicide bombers. The prosecutors say Abrini then threw away the jacket and sold the hat.

It was the latest evidence to link the two major attacks. Previously, authorities had said Brussels bomber Najim Laachraoui built explosives used in the Paris attacks.

However, Belgian terror analyst Pieter van Ostaeyen tells Teri that he "doesn't buy" Abrini's purported confession because it's not "Islamic State-style."

"I've been analyzing these guys' modus operandi in Europe since the beginning and this is just off," van Ostaeyen says. "There's no way some guy like Mohamed Abrini would go out and say 'I was the guy in the hat and I sold my hat' and I'm going to tell you everything about my network. No way. No way."

Van Ostaeyen adds that he believes there are more militant cells in Belgium, still planning attacks. Teri reports that Belgium has kept its threat level at three out of four, which puts the threat of an attack at "credible and possible."

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