HTC has filed its preliminary defense against Apple’s patent infringement lawsuit in a U.S. District Court in Delaware, according to court documents.

In the documents, the company claimed it lacks the “knowledge or information sufficient to form a belief as to the truth of the allegations contained in Paragraph 10 and on that basis den[ies] them.” Paragraph 10 in Apple’s original complaint covers the alleged patent infringement.

HTC posted a similar defense for the allegations laid out in paragraph 11 of Apple’s complaint, which asserts Apple’s ownership of the patents in question.

HTC also claimed four of the contested patents are invalid “failure to comply with one or more of the conditions for patentability set forth in Title 35 of the United States Code,” including utility, novelty, non-obviousness, enablement, written description and definiteness, or are invalid on the grounds of double patenting.

Apple filed its second lawsuit against HTC in June, claiming the handset maker was violating four of its patents. The filing came after an earlier patent infringement lawsuit and a complaint filed with the International Trade Commission.