Delete the group from the site collection using SharePoint 2010 web service in powershell

Steps Involved:

Open SharePoint 2010 Management Shell by going to Start | All Programs | SharePoint | Microsoft SharePoint 2010 Products | SharePoint 2010 Management Shell (Run as Administrator).
Run the following script.

Powershell Script:

 
## Delete the group from the site collection using SharePoint 2010 web service in powershell
$uri="http://serverName:10736/sites/ECT/_vti_bin/UserGroup.asmx?wsdl" 
## $groupName is a string that contains group name to be deleted
[String]$groupName ="Group2"; 
## Web Service Reference - http://Site/_vti_bin/UserGroup.asmx
$usergroupWebServiceReference = New-WebServiceProxy -Uri $uri -UseDefaultCredential 
$usergroupWebServiceReference.RemoveGroup($groupName)

Using the above script you will able to delete a group from the current site collection.