Erro feed RSS

Pessoal, boa noite!

Estou tentando fazer um feed RSS e esta apresentando o erro abaixo, alguém já passou por isso?

This page contains the following errors:
error on line 2 at column 6: XML declaration allowed only at the start of the document
Below is a rendering of the page up to the first error

Segue código fonte.

<?php header('Content-Type: text/xml'); ?> <?php echo '<?xml version="1.0" encoding="utf-8"?>'; ?>
<title>Aliens Abducted Me - Newsfeed</title>

<link>localhost/cap12</link>

<description>Alien abduction reports from around the world courtesy of Owen and his abducted dog Fang.</description>

<language>en-us</language>
<?php require_once('connectvars.php'); // Connect to the database $dbc = mysqli_connect(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME); // Retrieve the alien sighting data from MySQL $query = "SELECT abduction_id, first_name, last_name, DATE_FORMAT(when_it_happened,'%a, %d %b %Y %T') AS when_it_happened_rfc, " . "alien_description, what_they_did FROM aliens_abduction ORDER BY when_it_happened DESC"; $data = mysqli_query($dbc, $query); // Loop through the array of alien sighting data, formatting it as RSS while ($row = mysqli_fetch_array($data)) { // Display each row as an RSS item echo ''; echo ' ' . $row['first_name'] . ' ' . $row['last_name'] . ' - ' . substr($row['alien_description'], 0, 32) . '...'; echo ' localhost/cap12/index.php?abduction_id=' . $row['abduction_id'] . ''; echo ' ' . $row['when_it_happened_rfc'] . ' ' . date('T') . ''; echo ' ' . $row['what_they_did'] . ''; echo ''; } ?>