An immigrant from Mexico who has been living in an Arizona church to avoid deportation has left its sanctuary for the first time in 15 months, following an agreement with immigration officials, her attorney has said.

Rosa Robles Loreto, originally from Mexico, is a mother of two and lived in Tuscon since 1999. She sought refuge in August 2014, just one day before she was scheduled to turn herself over to immigration officials for deportation back to Mexico.

Her case began in September 2010 when, on her drive to work, she drove on the wrong side of cones in a construction zone prompting a police officer to pull her over. This triggered deportation proceedings and she was detained for 53 days before being released and the government began formal deportation proceedings.

Over the past 15 months, supporters in Tuscon and further afield have campaigned to persuade immigration officials to grant Loreto reprieve.

Supporters have made thousands of phone calls to US officials. Many Tuscon locals have placed signs on their front lawns reading, "We Stand with Rosa."

She had stayed in the Southside Presbyterian Church for 461 days, describing the ordeal as "a struggle" to the Guardian. Her husband and two children did not have deportation orders and had been living at their home in Tuscon.

"There is no doubt in my mind that the amazing courage of Rosa and the steadfast support from thousands of Tucsonans have brought us to a resolution that ensures Rosa will be safe outside of the walls of Southside Presbyterian Church," her attorney Margo Cowan said.

Loreto, 42, was among more than a dozen undocumented immigrants who took shelter inside a network of activist churches last year. Some have received stays of deportation or other forms of deferred action on their proceedings.

Her decision to leave the church comes the same week the US 5th Circuit Court of Appeals upheld an injunction barring the Obama administration from implementing a policy of deferring deportation actions against more than 4 million undocumented immigrants.

Additional reporting by Reuters