The robbers raided several villages located in Maru local area of Nigeria`s northern state of Zamfara.
Eyewitnesses said the attack which lasted for three hours saw the gang move through Biya, Guru, Sabuwar Kasuwa and Dansadau villages shooting and robbing people of their money and other possessions.
"They killed eighteen persons at Dan Gulbi market alone and left eight others seriously injured," a witness told PTI adding, that they continued with their attacks by entering a neighbouring Biya village where they killed three persons.
Then they went to Guru and Sabuwar Kasuwa villages where they shot dead a person in each of the villages, she continued.
"An injured person who was taken to the Federal Medical Centre Gusau for attention also died," she said.
According to her, she was able to escape by hiding under a pyramid of abandoned sacs where she heard the gunmen shouting at and killing a person who did not give them money.
"Our camp needs foodstuffs and other necessities and we must do whatever we can to get our stores loaded," she quoted one of the bandits as telling a man who was begging desperately for his life.
Police spokesman for the state, Sanusi Amiru said a top police functionary was on his way to the affected areas.
Robbery attacks in villages in the state are common.
Last year, similar attack on villages of Lingyado, Tungar and Baushe left over 30 persons dead.
Northern Nigeria has been bedevilled by an Islamic sect, Boko Haram which has vowed to install Sharia rule in the country.
They engage in suicide bombing and shooting but the present attack appear to be the handiwork of armed robbers.