Recently, unmanned underwater vehicles (UUVs) have been proposed for many applications including environmental monitoring, the oil industry, aquatic life research, law enforcement and military applications. One particular military application involves using UUVs for mine countermeasure (MCM) operations. In 2003 during operation 'Iraqi Freedom' a Hydroid REMUS UUV was first used to search for mines in the Northern Arabian Gulf as part of a live MCM exercise. Since then the idea of using these types of vehicles for MCM has gained much popularity. In recent years many companies, academic institutions, and research organizations have taken it upon themselves to create mission planning software for UUV operations that provide an operator with many tools to easily create missions. However, many of these tools still require the operator to do much of the work by hand. Even during mission execution the operator may be required to intervene to resolve any issues that may arise with a particular vehicle and re-task the remaining vehicles. Some of the existing tools do offer these dynamic mission planning capabilities, but many of the other tools out there do not. Our main focuses in this paper is to extend this previous work by offering a new tool that allows an operator to easily specify MCM missions using a graphical interface, automatically generate a set of tasks for a group of cooperating UUVs and provide the operator with the ability to automatically re-plan certain aspects of the mission while it executes. Our tool offers two main benefits. First, the operator can easily create missions without having to write a single line of source code or worry about details of generating a set of tasks for a group of UUVs. Second, our tool alleviates the operator from the burden of manually re-tasking vehicles during mission execution as mission parameters and objectives change. We hope our proposed tool will further reduce any potential errors introduced to the mission and lend towards successful mission creation and completion for a group of cooperating UUVs.