The United States is warning its citizens of the dangers of traveling to South Sudan, despite the celebration of the country's new independence.

The U.S. embassy in South Sudan urged Americans Tuesday not to travel to border regions between Sudan and South Sudan, citing recent fighting between forces loyal to the two countries' armies as well as a buildup of troops on both sides of the border. The embassy says in addition to the fighting on the ground, the Sudanese air force has bombed border areas in Unity and Southern Kordofan states.

The embassy also warned of the danger of violence in all areas of South Sudan, saying there are at least seven different rebel militia forces that frequently clash with South Sudanese forces.

It says the government of South Sudan has limited capacity to deter crime outside of the capital city of Juba and that even there, the risk of violent crime is high.

South Sudan became a new nation on Saturday after its residents voted overwhelmingly to split from the north in a January referendum. The former two halves of Sudan fought a 21-year civil war that ended in 2005.

Sudan and South Sudan have several unresolved disputes, including who will control the oil-rich Abyei region and how to share oil revenue.

South Sudan is also one of the least developed countries on the planet. Its capital has only a few dozen kilometers of paved roads, and most of the country's people cannot read.

Despite the obstacles, southern Sudanese are hopeful for their country, and hundreds of thousands of people took part in the independence celebrations.