Regex to validate phone number with vee-validate

I am using vee-validate for field validation, but my validation is not working using regex for a phone input.

<the-mask name="phone" :mask="['(##) ####-####', '(##) #####-####']" v-model="$parent.user.phone" v-validate="{ regex:/(^\(?\d{2}\)?[\s-]?[\s9]?\d{4}-?\d{4}$)?/ }"/>
<span class="validate-error" v-if="errors.first('phone')">Telefone inválido</span>