Prime Minister Shinzo Abe may have known of a new veterinary school project at the center of favoritism allegations against him roughly two years earlier than he has stated, a document obtained by Kyodo News showed Monday.

The revelation prompted opposition parties to renew their criticism of Abe, who has been under fire for allegedly using his influence in the approval process that led to the opening of Japan's first veterinary department in half a century by Kake Educational Institute last month.

Kotaro Kake, who heads the school operator, is a longtime friend of Abe. But the prime minister has repeatedly denied involvement in the approval process for the project, located in a special deregulation zone in Imabari in the western Japan prefecture of Ehime.

The new document, which was submitted by the Ehime prefectural government to the Diet on Monday, states Kake told Abe that the school operator aimed to provide veterinary education meeting international standards during a meeting on Feb. 25, 2015.

The prime minister has said he learned of the project on Jan. 20, 2017, when a government economic panel approved the project.

"The idea of opening such a new veterinary school is good," Abe said when he was told of the project, according to the document compiled by the prefecture.

In a statement released Monday night, the school operator denied that Kake and Abe had met on that day.

Suspicion deepened last month when another Ehime document was found stating a former secretary of Abe recommended that local government officials proceed with the plan, describing it as a "matter concerning the prime minister," during a meeting with them at the prime minister's office on April 2, 2015.

Tadao Yanase, the former secretary who is now vice minister for international affairs at the Ministry of Economy, Trade and Industry, had denied meeting with people involved in the project but later admitted to meeting with Kake officials on May 10 in the Diet.

The document recorded the local government officials' trip to Tokyo, including a meeting with Yanase.

Yuichiro Tamaki, co-head of the new Democratic Party for the People, told reporters, "Prime Minister Abe's Diet remarks have been turned upside down. The Cabinet should resign en masse."

Akira Koike, head of the secretariat of the opposition Japanese Communist Party, said, "This is an important document that should determine Prime Minister Abe's next course of action. Without thoroughly investigating this issue, the Diet will not move forward."