Answer by taking a quote from the following article:

The North American fur trade was the industry and activities related to the acquisition, trade, exchange, and sale of animal furs in North America. Aboriginal peoples in Canada and Native Americans in the United States of different regions traded among themselves in the Pre-Columbian Era, but Europeans participated in the trade beginning from the time of their arrival in the New World and extended its reach to Europe. The French started trading in the 16th century, the English established trading posts on Hudson Bay in present-day Canada in the 17th century, and the Dutch had trade by the same time in New Netherland. The 19th-century North American fur trade, when the industry was at its peak of economic importance, involved the development of elaborate trade networks.

At the beginning of the 18th century, more organized violence than in previous decades occurred between the Native Americans involved in the deerskin trade and white settlers, most famously the Yamasee War. This uprising of Indians against fur traders almost wiped out the European colonists in the southeast. The British promoted competition between tribes, and sold guns to both Creeks and Cherokees. This competition sprang out of the slave demand in the southeast - tribes would raid each other and sell prisoners into the slave trade of the colonizers. France tried to outlaw these raids because their allies, the Choctaws, Chickasaws, and Yazoos, bore the brunt of the slave trade. Guns and other modern weapons were essential trading items for the Native Americans to protect themselves from slave raids; motivation which drove the intensity of the deerksin trade. The need for Indian slaves decreased as African slaves began to be imported in larger quantities, and the focus returned to deerskins. The drive for Indian slaves also was diminished after the Yamasee War to avoid future uprisings.  The Yamasees had collected extensive debt in the first decade of the 1700s due to buying manufactured goods on credit from traders, and then not being able to produce enough deerskins to pay the debt later in the year. Indians who were not able to pay their debt were often enslaved. The practice of enslavement extended to the wives and children of the Yamasees in debt as well. This process frustrated the Yamasees and other tribes, who lodged complaints against the deceitful credit-loaning scheme traders had enforced, along with methods of cheating or trade. The Yamasees were a coastal tribe in the area that is now known as South Carolina, and most of the white-tailed deer herds had moved inland for the better environment. The Yamasees rose up against the English in South Carolina, and soon other tribes joined them, creating combatants from almost every nation in the South. The British were able to defeat the Indian coalition with help from the Cherokees, cementing a pre-existing trade partnership.  After the uprisings, the Native Americans returned to making alliances with the European powers, using political savvy to get the best deals by playing the three nations off each other. The Creeks were particularly good at manipulation - they had begun trading with South Carolina in the last years of the 17th century and became a trusted deerskin provider. The Creeks were already a wealthy tribe due to their control over the most valuable hunting lands, especially when compared to the impoverished Cherokees. Due to allying with the British during the Yamasee War, the Cherokees lacked Indian trading partners and could not break with Britain to negotiate with France or Spain.

What wa the cause of the increase in violence?
British promoted competition between tribes, and sold guns to both Creeks and Cherokees.