West Ham United manager Slaven Bilic has vowed to punish any players who broke club rules during their night out last month.

Bilic allowed his players to go out on a bonding session on the Monday night following their 3-0 defeat to Southampton, but reports surfaced the following day claiming that Andy Carroll and Darren Randolph were still drunk.

Bilic promised to open an investigation into the incident following their match against Middlesbrough before the international break, but he admitted that the probe is still ongoing.

"It's still not over. It is an old story and it is not very important now. It is not done yet," he told reporters.

"It is not easy, I can't do the investigation because it didn't happen on the pitch. I'm going to react but it isn't done and I don't think about that at the moment, I am thinking about our next game.

"I can only repeat what I said before, it was my decision. If they stepped out of the line of the rules of our club, they will be punished."

The Hammers face Crystal Palace on Saturday looking to end a five-match winless streak that has seen them claim just one point.