"It comes at a very critical moment for the Republic of South Sudan because our neighbor, Khartoum, has declared war against the Republic of South Sudan," Salva Kirr said while in Beijing for talks with Chinese President Hu Jintao.
At least three people, including a young boy, have been killed, allegedly by Sudanese warplane bombings, the Voice of America reported Monday.
"What happens in the next few days is very crucial on whether the two countries can avert the possibility of an outbreak of a full-blown conflict, or if they actually lead themselves headlong into a situation of all-out war," said South Sudan's deputy defense minister, Majak D'Agoot.
A spokesman for the United Nations High Commissioner for Refugees, Adrian Edwards, said the hostilities have displaced more than 35,000 people in Sudan's South Kordofan province who have left for Unity state.
Edwards said the number of refugees is on an increase with some of them "seriously malnourished," the United Nations reported.
The UNHCR is urging the governments of Sudan and South Sudan to "do their utmost to avoid displaced civilians being placed in harm's way, and to avoid actions that could displace more people," Edwards said.
He added humanitarian agencies including the World Food Program will distribute food to 2.7 million people.
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