European semiconductor manufacturer ASML and its strategic partner Carl Zeiss (ETR:AFX) today filed a patent infringement countersuit against Nikon (TYO:7731) in response to legal action taken by Nikon against the companies.

The suits involve semiconductor manufacturing equipment, flat panel display manufacturing equipment and digital cameras.

On Monday, Nikon filed its own patent case against ASML and Zeiss accusing them of using its lithography technology without permission. ASML denies any infringement and said there was no choice but to file countersuits.

“Now that Nikon has decided to take this dispute to court, we also have to enforce our patent portfolio, and we will do this as broadly as possible,” ASML CEO Peter Wennink said in a statement, adding that it has tried for years to come to a cross-licensing agreement with Nikon.

Nikon has not yet commented on the legal actions.

Material from Reuters was used in this report.