A spokesman for the opposition says the two sides have agreed to a "month of tranquility," starting on May 7.
But each side says their opponents should be worried by the threat of sanctions, and South Sudan's Foreign Minister holds talks with US officials in Juba to try to have the executive order withdrawn.
The camp is a joint venture of the U.N. Mission in South Sudan, the government and the Chinese embassy, and is expected to be ready in six weeks.
A spokesman for the government says the army pulled back to positions just outside the town after rebels launched an attack earlier this week.
South Sudan government expresses surprise as Information Minister is denied permission to enter U.N.site in Bor where 10,000 people are sheltering, but the U.N.says it is merely enforcing its no-weapons rule and remaining neutral in the five-week conflict.
Officials blame rebels led by David Yau Yau after more than 40 people are killed in an attack in South Sudan's Jonglei state, but Yau Yau denies his fighters had anything to do with the assault.
