plpgsql: Is ELSE IF supported or not?

Docs seems to say it is, but following function fails to compile:

create function err_else() returns void as $$
begin   if 1 = 1 then   else if 1 = 2 then   end if;
end;
$$ language plpgsql;

ERROR:  syntax error at or near ";"
LINE 6: end;

Version 8.3.3.

-- 
marko