UPDATE 2 -- 12 Noon PDT, February 2: Ubisoft has now issued a new statement on the matter.

"After further investigation into the matter of keys that were fraudulently purchased on EA's Origin store, we are reinstating keys for consumers who already had successfully activated and started playing the games. Any remaining fraudulently obtained and resold keys have been deactivated.

"We are working with EA to prevent situations like this from happening again, and we will continue to deactivate keys that are found to be fraudulently obtained and resold. We strongly recommend that players purchase keys and downloadable games only from the Uplay shop or trusted retailers."

UPDATE 3PM PST: Ubisoft issued the following statement regarding the grey market games getting blocked:

"We strongly recommend that players purchase keys and downloadable games only from the Uplay Store or their trusted retailers. We regularly work with our authorized resellers to identify and deactivate fraudulently obtained and resold keys. In this case, we confirmed activation keys were recently purchased from EA’s Origin store using fraudulent credit card information and then resold online. These keys may have been deactivated. Customers who may have been impacted should contact the vendor where they purchased the key for a refund."

The original story appears below.

Ubisoft has begun blocking access to some of its PC games having discovered they were acquired on the gray market.

A certain number of PC games reseller sites, such as G2Play and Kinguin, have come under scrutiny in recent months as they are known to sell Steam game codes at prices well below market value. It is how resellers buy these keys in the first place that many publishers and developers have scrutinized.

Now it emerges that Ubisoft commenced deactivating some PC games, such as Far Cry 4 and Assassin's Creed Unity, having determined they were acquired by resellers.

Consumers have already raised complaints about their games being deactivated on the Ubisoft forum, but the publisher insists this is a legal matter.

"We regularly deactivate keys that were fraudulently obtained and resold," the corporation told Eurogamer.

"In this case, we are currently investigating the origin of the fraud, and will update customers as soon as we have more information to share. In the meantime, customers should contact the vendor from whom they purchased the key."

Ubisoft is not the first company to take measures against grey market resellers. In May last year, Hotline Miami publisher Devolver Digital declared it was "actively cancelling" Steam keys sold on the reseller website G2A.