A US border security chief says he has temporarily stopped launching criminal prosecutions of migrants who illegally enter the country with children.

Customs and Border Protection (CBP) Commissioner Kevin McAleenan told reporters in Texas the prosecution referrals were suspended last week.

He said it followed an order last week by President Donald Trump calling for an end to migrant family separations.

But Mr Trump had suggested the families would instead be detained together.

The Republican president bowed to public pressure last Wednesday, signing his executive order to "keep families together" in migrant detentions.

Mr McAleenan maintained that the Trump administration's "zero tolerance" tactics were still in effect, although the commissioner's guidance to his agents largely leaves the policy in limbo.

• Migrant families face chaos to reunite

The CBP chief said parents cannot be prosecuted if US officials no longer intend to separate them from their children, who are legally not allowed to be kept in adult detention facilities.