UN High Commissioner for Refugees (UNHCR) spokesman Adrian Edwards on Tuesday said that heavy fighting in South Sudan over the last two months has displaced more than 100,000 people.

The fighting there also blocked humanitarian aid deliveries for some 650,000 people as aid organizations were forced to withdraw, the spokesman said

Since the beginning of the year, some 60,000 South Sudanese have fled the country, mostly to Sudan (30,000), to Ethiopia (15,000) and to Uganda (15,000) bringing the total South Sudanese who fled the country since December 2013 to some 555,000, while some 1.5 million are internally displaced in the country, the spokesman added.

Refugees cite the upsurge in fighting, but also growing food insecurity as the main reasons for fleeing their homes. It's estimated that more than 3.8 million people, representing a third of South Sudan's population of 11 million, do not have sufficient food, he said.