July 15, 2013: A man injured during tribal clashes in Jonglei State sits in a hospital in Bor, South Sudan Camille Lepage/AFP

Dozens of hospital patients have been killed in South Sudan, amid increasing violence due to the civil war which erupted in the country last December.

NGO Medecins Sans Frontieres (MSF) said that the violence is the worst seen in decades and the killings are an "affront to human dignity."

"The conflict has at times seen horrific levels of violence, including against healthcare facilities," said Raphael Gorgeu, South Sudan chief for MSF.

"Patients have been shot in their beds, and lifesaving medical facilities have been burned and effectively destroyed. These attacks have far-reaching consequences for hundreds of thousands of people who are cut off from medical services."

According to MSF at least 58 people were killed in four hospitals in recent attacks.

"Throughout its 30-year history in the country, MSF -- as well as other humanitarian organisations and healthcare providers -- has repeatedly witnessed violence against staff, patients, vehicles, compounds and healthcare facilities," the NGO said in a report.

"What has been particularly alarming in the current conflict, however, has been the scale and breadth of the violence."