A co-chairman of Mitt Romney’s Arizona presidential campaign and elected official Paul Babeu has been forced to resign amid claims he had threatened to have a gay lover deported.

Babeu had had a relationship with a Mexican man, referred to only as Jose, and has acknowledged publicly for the first time that he is gay.

But he denies the claims he had threatened Jose with deportation after they separated.

Babeu, 43, is Pinal County, Arizona’s elected sheriff and a Republican strict on border control.

He had been working as a co-chair for Romney’s presidential nomination bid in the state of Arizona, which will hold its party primary next week.

But last week, Babeu’s former lover, Jose, went to the Phoenix New Times with a lawyer saying Babeu had threatened him after Jose refused to keep their relationship secret.

The paper then published a series of images of Babeu in underwear and taken from the Adam4Adam gay dating site as well as text message exchanges Jose said took place between the two men last year.

Babeu has said he believes Jose is not remaining in America illegally and added that he does not have the power to deport people personally.

The official had announced a desire to run for the US House of Representatives in October last year. He has so far said he will pursue this campaign but has distanced himself from Romney’s presidential bid.

Romney’s office said: “Sheriff Babeu has stepped down from his volunteer position with the campaign so he can focus on the allegations against him. We support his decision.”