I should warn you about something. The tanks won't stop at nothing. As a result, you have to watch out for your squad members. Make sure that no one gets in their way. The tanks should be able to reach the tunnel entrance within a few seconds (#1). You will have to wait for new orders. CHECKPOINT 5.
This isn't an obvious objective. You will have to clear out a nearby tunnel. That's where the terrorists have prepared a trap. Gather the rest of the team around your position. Start moving towards the tunnel (#2).
The blockade is located just around the corner (on your left). The most important thing is that you take out two soldiers armed with rocket launchers (#1). Once they're gone, deal with the remaining enemy units (especially the gunner). The tanks should enter the tunnel. Wait for them to reach the opposite end of it. That's where they will stop again (#2). You will receive some new orders from the commanding officer. CHECKPOINT 6.