By Phil Stewart
JUBA, May 2 (Reuters) - U.S. Secretary of State John Kerry flew into South Sudan on Friday to push for a halt to more than four months of fighting in Africa's newest nation, a message he was expected to deliver in talks with President Salva Kiir.
Kerry's trip to South Sudan, his first as secretary of state, came a day after he renewed U.S. threats of sanctions and held out hope for the rapid deployment of more peacekeepers. He said the conflict could descend into genocide.
"Secretary Kerry will reiterate the need for all parties to respect the cessation of hostilities agreement, to immediately cease attacks on civilians, and to fully cooperate with the United Nations and humanitarian organizations," said State Department spokeswoman Jen Psaki.
More than 1 million people have fled their homes since fighting erupted in December between troops backing Kiir and soldiers loyal to his sacked deputy, Riek Machar.
The fighting has largely run along ethnic lines between Kiir's Dinka people and Machar's Nuer.
Thousands of people have been killed and tens of thousands have sought refuge from the violence at U.N. bases around South Sudan, a country the size of France that secured independence in 2011 when it split from its northern neighbour, Sudan.
Kerry, speaking on Thursday in Ethiopia after talks with regional states, warned of the risks of genocide in South Sudan and said all sides agreed the "killing must stop".
Kerry lamented violence on both sides and called upon Kiir and Machar to publicly "condemn the brutal attacks that are taking place against innocent people." (Additional reporting by Carl Odera; Editing by Edmund Blair)