Afton Mayor Patricia M. Snyder is stepping down to focus on the security company she runs with her husband, city officials announced Wednesday.

Her decision, which comes with a year left in her current term, caught most officials by surprise.

“What I know is that she has been very, very busy with her business that she has,” said Ronald Moorse, the city’s administrator. “I was under the impression that she was very busy, but that was going to, at some point, change. And I didn’t have any idea that there would be a resignation.”

Moorse said the City Council will hold a special meeting Thursday to discuss how to proceed. In the meantime, council member Joe Richter will serve as mayor pro tem.

The council’s choice for interim mayor will serve out the rest of Snyder’s two-year term, which expires in 2014.