Four men charged in an alleged plot to join Islamic State appeared together in federal court for the first time Wednesday.

Dilkhayot Kasimov is the latest to be accused in the case.

He's charged with conspiracy and attempting to provide material support to terrorists.

Prosecutors say the 26-year-old from Uzbekistan provided financial support to three other Brooklyn men who planned to fly to Turkey and then Syria to join the terrorist group.

Those three men pleaded not guilty to additional charges Wednesday.

In court, a prosecutor said Kasimov's role was "tantamount to providing money to slaughter innocent victims.'' 

Kasimov's attorney, Adam Perlmutter, says his client is young and impressionable and may have been led on by an FBI informant.  

"We know from experience that since 9/11, there have been many many cases that the FBI has brought that they designate as terrorism cases. But when you parse through that list, what we realize is that a large majority of them are cases where they have taken people's expressions of religious beliefs and brought in agent provocateurs to try to get those people to act on those beliefs," says Perlmutter.

The three co-defendants were originally arrested in February—two in Brooklyn and one in Florida.