Dead3yez informed us on our forums of a campaign called CHASE 13 that he is working on.

Quote Dead3yez:
This is a singleplayer/multiplayer mini-campaign I am working on. It will be addon free and will contain four main missions. The first release will be singleplayer then I will work on making it multiplayer compatible.

Stockpiles of nerve agents that were smuggled into Afghanistan during the Soviet-Afghan war era have been "re-discovered". There is no evidence of importation of the encased chemicals. It is discovered that the US plans invasion on Iran to gain territorial control and oil resources. The US is to re-activate and use these toxic substances to stage an Iranian chemical attack against its own troops. UK and Russian intelligence agencies work together to un-cover the US's secret ambitions. UK and Russia conspire against the US by conducting a vital operation to prevent the invasion..

You can find more information and leave your feedback in the CHASE 13 Campaign WIP topic.