Are attacks obligatory?

hi all,
during the last game session the following situation came up:
one brethren was in close combat with four skaven warriors (all henchmen).
The first two skaven stunned the brethren and the skaven player wanted to skip the attacks of the other two skaven,
as he wanted to bring in a hero next round so that he may benefit from the extra experience for ooA an enemy model.

So my question is: Can a player choose to skip the cc-attacks of his models or not? Or do they simply attack once they are in close combat?
We played that the models must attack as I couldn't remember any section of the rules saying that you may choose not to attack. On the other hand it is nowhere stated explicitly that you have to... I guess...

Historically, in most GW games you must attack if in base contact, so I think you played it correctly.

I can see a hero barking commands at his underlings to leave a downed enemy alone so he/she/it can finish them off, it hasn't come up in our games but we would play it that u can leave them after passing a leadership test? To show them controlling themselves in the face of an easy kill

If they are in base to base contact, they can either fight or they can try to escape the combat and run away. The other model gets to attack while the first one is running away.

Rules say, that all models in hand-to-hand combat must fight:

Mordheim Rulebook, page 18 wrote:

Models whose bases are touching are engaged in hand-to-hand combat. This can only happen once a warrior has charged his enemy, as models are otherwise not allowed to move into contact. All close quarter fighting is worked out in the hand-to-hand combat phase. Regardless of whose turn it is, all models in hand-to-hand combat will fight.

Then again, if the model was knocked down or stunned, the attackers can move on to other targets and leave the downed model alone. All the models must fight first though - your 4 skaven need to attack the brethren on this combat round.

Mordheim Rulebook, page 21 wrote:

The exception to this rule is that if all a model’s close combat opponents are knocked down or stunned, he may move away from the combat if you wish, and even charge other enemies within range.

So yes, you played correctly and according to the rules.

@elde--Thanks for posting the relevant rules. Welcome to the forum!

SonofRuss's idea would make a pretty cool house rule