Start moving forward. Stand by a yellow van (#1). The current mission objective is going to be delayed. There's a new task for you to deal with at this particular moment. CHECKPOINT 4.
First of all, you should know that there are THREE enemy machine gun posts in the area. You will have to take them out. The first machine gun post is located at the opposite end of this alley (#2). You will have to order your team to hold this position or to retreat. The objective is to not let them being harmed by the machine gun fire.
I would recommend that you try and surprise the gunner from the left side. If you're quick enough, you should be able to take him out without being harmed (#1). You must aim at his head, as this is the only weak spot. Head on to this location (with the whole team). The second machine gun post is on your right (#2).
Head on to the small alley (alone). If you're lucky, you should be able to surprise a soldier who's standing by the second machine gun post (#1). Once he's gone, order your team to join you. Now you will have to turn left. There's a large street ahead of you (#2). Take out the visible enemy soldiers before you decide to move on any further. The rest of the team should help you in these fights.
The rest of the team MUST remain here. Otherwise you would have lost your entire squad. The last machine gun post is located at the opposite end of this street. Just as before, we'll try and surprise the gunner. Start moving forward. Once you're closer to the machine gun post, lie down on the ground. Keep moving forward (#1). Try moving to your right. You should be able to kill the gunner (#2). This time you may try aiming at his legs. Alternatively, you could also use the grenades. Once he's gone, order the rest of the team to join you. Your team members will probably take care of a few additional terrorists along the way. Don't worry. They'll be fine.
Wait for the whole team to show up. Turn right. You will have to start moving forward (#1). We'll take care of the well-defended vehicle first. Once you've reached a small junction, turn right (#2). That's where the ADAT is going to be located.
You shouldn't have any major problems locating the first ADAT (#1). Notice that there are a lot of terrorists standing by it. DON'T even think about getting closer. Instead, we'll destroy the machine from here. You will have to be aiming at the ADAT. Enter the menu and choose the 'Attack' option (#2). The ADAT will explode in just a few seconds. Take care of those terrorists who have actually survived the attack.
You should know that an enemy humvee will arrive here very shortly (#1). Take out its gunner. Once he's gone, deal with the remaining enemy soldiers (#2). You could also use a rocket launcher or a couple of grenades, although these objects aren't necessary for this action to succeed.
Finding the second ADAT isn't as easy as it seems. The vehicle is located near the third machine gun post. It should be parked by one of the buildings (#1). Just as before, you will have to organize an air strike in order to get rid of it (#2). As a result, you will complete this mission objective. Get ready for the next one.