Phone number validation in php codeigniter

This is always work for me:

$this->form_validation->set_rules('mobile', 'Mobile Number ', 'required|regex_match[/^[0-9]{10}$/]'); //{10} for 10 digits number

take a look at the following. regex for international numbers. You will need to check against multiple regex. If the number does not match the first regex(us phone numbers) then check it against the international regex. If neither match, fail the test