$re = '/https?://(?:(?:www|m(?:obile)?)\.)?twitter\.com/(?:(?:i/web|[^/]+)/status|statuses)/(?P<id>\d+)/m';
$str = 'https://twitter.com/VictorKvert2008/statuses/1251621111357456384';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php