We analyse the classical symmetries of bosonic D-string actions and ge
neralizations thereof. Among others, we show that the simplest actions
of this type have infinitely many nontrivial rigid symmetries which a
ct nontrivially and nonlinearly both on the target space coordinates a
nd on the U(1) gauge field, and form a Kar-Moody version of the Weyl a
lgebra (= Poincare algebra + dilatations). (C) 1998 Elsevier Science B
.V.