Is there any way I could improve this piece of PHP code?

Is there a way I could make this code simpler or smaller? i.e. in one line, instead of an if statement inside an if statement? Just to clarify, this works perfect, but I feel like there should be something way easier than this.

if (isset($_GET["update"])) {
    if ($_GET["update"] == "false") {
    echo '
    <br>
    <div class="container">
        <div class="alert alert-danger" role="alert">
          <strong>FEIL!</strong> Du må velge en ansatt før du kan gjøre det.
        </div>
    </div>
       ';
   }
}