A Taiwan university has filed a patent infringement suit against Apple over Siri speech recognition system, which lets users perform tasks with voice commands.

Apple introduced the voice-activated assistant technology when launching the iPhone 4S in 2011.

Cheng Kung University in south Taiwan's Tainan city said the technology infringes two patents held by its research teams, both related to speech recognition.

The suit was filed in the United States District Court for the Eastern District of Texas, Marshall Division, on Friday.

The amount of compensation the university is seeking is not clear.

Earlier this month, Chinese technology firm Shanghai Zhizhen Network Technology Co Ltd filed a similar claim against Apple over Siri.