xml declaration allowed only at the start of the documentkohana2

Im trying to generate xml document but it keeps on display this error

  This page contains the following errors:

 error on line 12 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.

  http://ift.tt/1w9JPxh 1232 daily

I am sure there are no whitespaces

<?php header('Content-type: application/xml'); ?>
<?xml version="1.0" encoding="UTF-8"?>
<urlset
xmlns:xsi="http://ift.tt/ra1lAU"
xsi:schemaLocation="http://ift.tt/xwbjRF http://ift.tt/Av6BHN"
xmlns="http://ift.tt/xwbjRF">
<url>
<loc>http://ift.tt/1mmWr3f;
<lastmod>1232</lastmod>
<changefreq>daily</changefreq>
</url>
</urlset>