Prime Minister Shinzo Abe, facing a grilling from opposition lawmakers amid sagging support for his Cabinet, denied Monday favoritism allegations against him that have been blamed for his party's losses in two recent major local elections.

Abe told an ad hoc session of the House of Representatives Budget Committee that he was not asked by a friend for help in opening a new university department, and that he did not instruct government officials to benefit the friend's school operator.

Abe has faced allegations that he used his influence to sway the approval process for a new veterinary department of a private university run by Kake Educational Institution in a special economic zone. The group is headed by Abe's friend Kotaro Kake.

While he had bristled at any suggestion of preferential treatment as an "image-manipulation" attempt by the opposition, the prime minister on Monday appeared to admit his own fault in the way he used to address the issue in parliament. "It is natural for the public to skeptically view the issue, which involves my friend. I lacked the perspective," he said.

After his Liberal Democratic Party initially refused to let Abe appear before parliament, he agreed to face questions from lawmakers over the issue after suffering a crushing defeat in the Tokyo metropolitan assembly election earlier this month.

Abe's appearance before the committee, a one-off meeting arranged after the Diet session ended last month, comes in the wake of a fresh defeat for the LDP in a local election the previous day. An opposition-backed candidate beat her LDP-backed rival in the mayoral election in Sendai, northeastern Japan.

While members of the Abe administration have repeatedly denied the favoritism allegations, the education ministry's internal documents indicated officials of the prime minister's office and the Cabinet Office, which oversees specially deregulated economic zones, pressured the ministry before Kake's selection in January.

Before Kake, no school operator was permitted to open a new vet school in half a century in Japan amid concern about a glut of animal doctors.

Kihei Maekawa, a former top education ministry bureaucrat who has drawn attention after publicly vouching for the authenticity of the documents and revealing pre-approval interactions between ministries and the prime minister's office, was summoned as an unsworn witness.

The former vice minister of the Ministry of Education, Culture, Sports, Science and Technology testified earlier this month in the Diet that the prime minister's office "worked behind the scenes" in the selection of Kake.

On Monday, Maekawa reiterated his assertion that Abe's aide Hiroto Izumi had urged him to speed up the process. Izumi is said to have made the request on behalf of Abe, saying "because the prime minister cannot say it himself."

Izumi, who appeared before parliament for the first time over the matter, however, denied making the remark.

In response to Hiroshi Ogushi, policy chief of the main opposition Democratic Party, who asked him to come to the Diet again as a sworn witness, the Abe aide only said he would abide by whatever decision is taken by parliament.

Opposition lawmakers also questioned Abe over claims Defense Minister Tomomi Inada in February allowed officials to conceal the existence of data on the Ground Self-Defense Force's daily activities in South Sudan during its U.N. mission, following reports last week about her alleged role over the issue.

The ministry had previously said the actual logs of the activities had been discarded, but their data had actually been preserved by a GSDF member. The logs contained controversial information pertaining to the security situation in the South Sudan capital of Juba where ground troops were operating.

Abe refused Ogushi's call for Inada's dismissal, saying he believes the defense minister will carry out a thorough probe over the issue and, if necessary, take preventive measures.

The Inspector General's Office of Legal Compliance, a special organization conducting the probe under the direct control of the defense minister, is currently looking into the suspected coverup. In a rare move, Inada has allowed herself to be questioned by the inspectors because of allegations about her own role in the matter.

Parliament is not currently sitting after the most recent ordinary session ended on June 18. Since then, ruling and opposition party lawmakers have held meetings to discuss the Abe favoritism allegations on July 10, while the premier was abroad to attend the Group of 20 meeting in Germany.

A similar session involving Abe will be held in the House of Councillors on Tuesday.