Nihon University's response to a protest by the Kwansei Gakuin University American football team over a dangerous tackle was insincere and the relationship between the teams is broken, officials of the school said Thursday.

Kwansei Gakuin University team director Hiromu Ono was joined by head coach Hideaki Toriuchi in a press conference where the two said the explanation provided by Nihon University, known as Nichidai, was not good enough.

In the now-infamous May 6 game in Tokyo, Kwansei's quarterback was cut down from behind by a Nichidai defensive player, causing knee and spinal ligament injuries. The blatant cheap shot was well away from the play and seemingly premeditated.

In the letter received Tuesday, Ono said the Tokyo-based Nichidai extended "heartfelt apologies" and denied instructing players to commit any deliberate dirty acts against Kwansei.

But Ono said the relationship between the two universities which are longtime rivals in the annual Rice Bowl -- the title game between Japan's corporate and university champions -- was broken in seconds.

"A collapse in our relationship of trust with Nichidai is what we're seeing," Ono said.

"(The letter) hasn't erased our doubts (about the play) and it's difficult to call this a sincere response," he said.

On Thursday, Ono said his side requested that the injured quarterback and his family receive personal apologies from the director and coach of Nichidai.

(Nihon Univ. coach Masato Uchida has denied any wrongdoing.)

He also revealed that Nichidai promised to give specific answers by May 24 and has been notified that Kwansei may cancel any future games between them.

Meanwhile, Toriuchi had questions about the way Nichidai coach Masato Uchida handled the matter, saying it is difficult to believe that the incident was a result of a coach-player miscommunication as claimed.

"He was there watching. If he says the player misunderstood his instructions, why couldn't he clarify that when it happened?" Toriuchi said.

"If we allow that kind of play to happen, the concept of sports is dead. It's crazy it took them so long to apologize," he said.

The Kantoh Collegiate Football Association announced Thursday that Nichidai's games against Seikei University and Meiji University have been cancelled. On Monday, three other schools in Tokyo called off games against Nichidai as a result of the foul play.