Parsing XML in Groovy

I've read through the documentation, but can't get this working. What I'm trying to do is parse this XML string

<?xml version="1.0" encoding="UTF-8"?>
<soapenv:Envelope xmlns:soapenv="http://ift.tt/sVJIaE">
    <soapenv:Body>
        <soapenv:Fault>
            <faultcode>soapenv:Server</faultcode>
            <faultstring>TriggeredMessageFault</faultstring>
            <detail>
                <TriggeredMessageFault xmlns="urn:fault.domain.com">
                    <exceptionCode>INVALID_PARAMETER</exceptionCode>
                    <exceptionMessage>Invalid campaign object</exceptionMessage>
                </TriggeredMessageFault>
            </detail>
        </soapenv:Fault>
    </soapenv:Body>
</soapenv:Envelope>

What I'm trying to do is get to exceptionCode and exceptionMessage and store those in two different variables.