Talks have begun in Ethiopia between South Sudan's government and rebels in a fresh effort to end the civil war, with the US secretary of state, John Kerry, in attendance.

Following a separate meeting with Kerry, Ethiopian Foreign Minister Tedros Adhanom said diplomats agreed that a peacekeeping force needed to be deployed soon.

"There is an agreement that we have to be as aggressive as possible in order to have an impact on the ground in South Sudan," Adhanom told reporters with Kerry and foreign ministers from Kenya and Uganda.

Fighting has intensified over the past two weeks despite a ceasefire being signed in January. It is feared thousands have been killed and more than a million people have been left homeless since the conflict started in December.

Al Jazeera's Anna Cavell reports from Juba, South Sudan.