ABUJA, July 23 (Xinhua) -- The Nigerian army, in a wave of cleanup operation, has killed 78 armed men in the country's restive northwest region, the military said on Tuesday.

The air-and-ground operation was conducted in various parts in the northwest state of Zamfara and neighboring states from May to July, resulting in the death of 78 armed men and seizure of a high amount of arms and ammunition, Onyema Nwachukwu, the military spokesperson, told reporters in Abuja, Nigeria's capital.

He added that the military operation successfully rescued over 50 kidnapped victims, noting that over 25 suspected armed group members were arrested.

Nwachukwu said the troops also recovered seven motorcycles used by armed groups and 695 cattle, adding that the cows had since been returned to their owners.

He reassured Nigerians, particularly residents of Kaduna, Zamfara and other affected states, that the military and other security agencies were fully committed to ensuring their safety and security.

He also urged the public to promptly report suspicious movements and activities in their localities to the nearest security agency.

Nigeria's Chief of Defense Staff Gabriel Olonisakin had constituted Joint Task Force Operation Thunder Strike (JTF OPTS) in May to tackle the problems of insecurity on Abuja-Kaduna highway and other adjoining communities.

The northern part of Nigeria has witnessed a series of attacks by armed groups in recent months.