First go to the place where the tanks are. Don't help the two dudes
behind the sandbags. Go to the guy behind the box and then kill the
enemies. Then the guy behind the box will shoot the pipe above the tank
and it blows up the tank. Now follow the guy with the bazooka and be
careful cause there's about 8 guys the dude with the bazooka will blow
up a couple of guys. You kill the rest. keep following him till he
destroys the second tank and you're done.