The group, which is called Our Principles PAC, is founded by Katie Packer, a veteran Republican strategist who served as deputy campaign manager on Mitt Romney’s 2012 presidential campaign.

This week, the group sent out mailers to Iowa voters attacking Trump, who polls show is in a tight battle with Ted Cruz in the state, where caucuses are to be held on Feb. 1. In a filing with the Federal Election Commission, the group has reported spending nearly $45,000 on mailers.

Packer has spent months in talks with Republican donors and operatives to gauge financial interest in an anti-Trump campaign.

In a brief interview on Thursday, Packer wouldn’t comment on the group’s plans other than to say: “Our Principles PAC has focused on conservative principles and ensuring that voters have the necessary information to make a wise decision on Election Day.