In this image taken from TV an armed member of the security forces stood guard as emergency services attended the scene after an explosion in a main metro station in Brussels on Tuesday. AP The terrorist group ISIS has claimed responsibility for Tuesday's attacks in Brussels. It did so through online channels affiliated with the group, which is also known as the Islamic State, ISIL, or Daesh.

A statement from the Amaq Agency, which distributes news about ISIS, says ISIS fighters carried out the bombings that targeted an airport and a metro station, killing dozens.

Amaq's statement was followed by a claim from other ISIS-linked online channels that distributed a statement in several languages, including Arabic, English, French, and Russian.

The ISIS statement cites Belgium's involvement in a US-led anti-ISIS coalition. It threatens "dark days" in response to the West's "aggression against" the Islamic State, which holds territory in the Middle East.

It's likely that the statements come from ISIS itself, according to Charlie Winter, an expert on jihadist propaganda and a senior research associate at Georgia State University's Transcultural and Violence Initiative.

"A'maq is an official media outlet — a claim through A'maq is a real claim," Winter told Business Insider in an email. "Of course, they may be exaggerating level of involvement."

Rita Katz, an expert on ISIS propaganda and cofounder of the SITE Intelligence Group, also told Business Insider the Amaq statement was authentic.

J.M. Berger, an expert on terrorist social-media use and coauthor of the recent book "ISIS: The State of Terror," said, however, that Amaq's claim "doesn't offer details that suggest insider knowledge" about the Belgium plot.

The Amaq statement was timed to a different statement from another ISIS-affiliated channel on the secure messaging app Telegram, which ISIS is known to use to distribute statements and propaganda.

The statement, from a channel that distributes ISIS news in English, implored subscribers to post tweets using the hashtags #Bruxelles, #Brussel, and #Brussels. The statement said it was "top priority" for ISIS supporters to "fill our stuff into the Brussels hashtag on Twitter."

Subsequent statements posted on several ISIS-affiliated Telegram channels encouraged people to "please take part in this online battle" by flooding Brussels-related hashtags with ISIS propaganda.

It appeared to be part of a coordinated social-media response to the attacks, in which ISIS supporters providing templates of tweets for followers to send out.

More than two dozen people were reported killed and even more wounded after explosions ripped through Brussels airport and metro stations across the city Tuesday morning.