Until this point all enemies where not hard to beat, but the big guys near the radio tower annoyed me. In the end I was able to kill him by emptying my machine and handgun on him a few times. Every now and then he seems to drop his shield when being fired at. Also I noticed that when you try to climb the wall to the burning roof, a Molotov cocktail is thrown to you. I was unable to time this so it would also hurt the shielded guy.
So, my question: what's the best strategy here?
You need to get close to this opponent so that he swings his melee weapon at you.
When this happens scramble out of the way (Shift on PC w/ keyboard, B on Xbox controller or O on the PS3), this will leave him exposed and stationary for a short period of time, now is the moment to attack the target.
After a short time he will raise the shield again, so you might have to repeat this pattern a few times (if I remember correctly this first shield guy is also wearing armour, so requires more time than others that come later).
Later in the game you can obtain other options that make shield guys easier to deal with (counter melee attack built in to a scrambling-dodge, for example), but the basic strategy is the same - get close, force them to expose them self, counter attack.
