JERUSALEM (AFP) - Peace talks between South Sudan's warring factions must not be a "gimmick" to buy time to win the upper hand on the ground, U.S. Secretary of State John Kerry warned Sunday.
"Both parties need to put the interests of South Sudan above their own,"
Kerry told reporters in Jerusalem.
"The beginning of direct talks... is a very important step, but make no mistake it is only a first step. There's a lot more to do.
"Negotiations have to be serious, they cannot be a delay, (a) gimmick in order to continue the fighting and try to find advantage on the ground at the expense of the people of South Sudan," said Kerry.
Leaders must approach the talks "with courage, with resolve and with the clear intent of trying to find a political solution.”
Face-to-face peace talks between South Sudan's warring factions were due to begin in earnest Sunday, with artillery fire in Juba's government district underlining the risk of a slide into all-out civil war.
The talks in the Ethiopian capital Addis Ababa are aimed at ending three weeks of fighting that are feared to have killed thousands in the world's newest nation.
The conflict erupted on December 15, pitting army units loyal to President Salva Kiir against a loose alliance of ethnic militia and mutinous army commanders nominally headed by his rival, former vice president Riek Machar.
Aid workers have stepped up warnings of a worsening crisis for civilians affected by the conflict in the landlocked country of almost 11 million people.
The army continued Saturday to battle rebels in a bid to wrest back the strategic town of Bor, capital of Jonglei, one of the country's largest states.
There were reports of intense battles involving tanks and artillery on the outskirts of Bor, which has already changed hands three times since fighting began.
The U.S. embassy in South Sudan ordered a further pullout of staff on Friday because of the "deteriorating security situation", although Washington -- a key backer of the fledgling state -- insisted it remains committed to ending the violence.
But Kerry reiterated that Washington would "deny support and we will work to apply international pressure to any elements who attempt to use force to seize power".
Force "is not acceptable," he said, adding the world would be "watching very closely to see that a halt to the fighting on the ground takes place.”
Fighting started in oil-rich but impoverished South Sudan when Kiir accused Machar of attempting a coup.
Machar denied this, in turn accusing the president of conducting a violent purge of opponents.
