Making a phone call in an iOS application

I have some code which attempts to make a call within an application, but it doesn't seem to be working:

    UIApplication *myApp = [UIApplication sharedApplication];
    NSString *theCall = [NSString stringWithFormat:@"tel://%@",phone];
    NSLog(@"making call with %@",theCall);
    [myApp openURL:[NSURL URLWithString:theCall]];

Sometimes, the variable phone is something such as @"(102) 222-2222". How can I make a call with a phone number like this? Do I need to manually extract the numbers out of it and get rid of all the extra punctuation?