A German charity has accused the Libyan coast guard of threatening its crew members who were rescuing migrants in the Mediterranean Sea, causing at least one migrant to drown.

The German charity SOS Humanity, which operates the rescue ship Humanity 1, said the Libyan coast guard used violence and fired live bullets into the water during its “life-threatening intervention” on Saturday.

The charity said that many migrants who were aboard three unseaworthy boats bound for Europe were forced to jump into the water. The European Union has been funding the Libyan coast guard as part of efforts to stem the flow of migrants.

As part of the deal, the coast guard has intercepted migrants in Libyan and international waters and has returned them to Libya.