The Defense Ministry came under fire Tuesday from opposition lawmakers for allegedly violating the rights of Self-Defense Forces personnel.

The Liberal Democratic Party lashed the ministry over news reports that a unit directly under Defense Minister Toshimi Kitazawa tasked with information security has been monitoring SDF personnel's participation in lectures given by former SDF members, including an outspoken critic of the administration.

Despite the ministry's denial that it was putting SDF members under surveillance, the LDP is expected to use the issue to grill the administration.

One of the lectures at issue was given by LDP Upper House member Masahisa Sato, a former commander of Ground Self-Defense Force troops in Iraq and an outspoken critic of the administration.

Kitazawa told a news conference there is "no truth that an order was made to gather information on specific persons" and denied that the lecture by Sato was targeted for surveillance.

He said the unit continues to engage in the activities for which it was created but didn't elaborate on the nature of those activities.

The unit is tasked with gathering intelligence to prevent leaks of classified information.

The ministry came under fire from opposition lawmakers last year for allegedly regulating civilians' freedom of speech during events at SDF-related facilities.