.net - tilde symbol in IIS Medium Trust Environment throwing error -

i have setup application in medium trust environment(.net trust levels = medium) , trying load favicon using tilde(~) symbol in href throws error.

<link rel="shortcut icon" href="~/content/img/favicon.ico"/> 

if remove ~ sign error goes off.

i getting error below :

security exception

description: application attempted perform operation not allowed security policy. grant application required permission please contact system administrator or change application's trust level in configuration file.

exception details: system.security.securityexception: request permission of type 'system.security.permissions.securitypermission, mscorlib, version=4.0.0.0, culture=neutral, publickeytoken=b77a5c561934e089' failed.

any suggestions?

thanks