Israeli military forces said riots had been taking place near the border fence in Khan Younis, and they fired warning shots into a crowd they believed to be staging a protest, the BBC reported.
Witness said the group of men were farmers.
The BBC reported 10 people were injured in the incident, though Ynetnews.com put the number at 19.
Hamas spokesman Sami Abu Zuhri accused Israel of violating the Egyptian-brokered truce, which took hold Wednesday after eight days of cross-border fighting resulted in the deaths of 158 Palestinians, four Israeli citizens and two Israeli soldiers. The death tolls are based on provisional U.N. figures.
"We will contact the Egyptian mediator to discuss the incident," Zuhri said.