By Andrew Green
JUBA, May 11 (Reuters) - South Sudan's army and rebel forces accused each other on Sunday of breaking a ceasefire hours after it came into effect, charges that will frustrate international mediators who had pressured both sides to stop the ethnic-fuelled conflict.
President Salva Kiir and rebel commander Riek Machar met face to face on Friday to sign the deal - the second time the two sides have promised to stop fighting after an accord in January swiftly collapsed.
But Sudanese army spokesman Philip Aguer said his forces had been attacked in two positions in oil producing Unity State, one of them near the flashpoint town of Bentiu, where an ethnic massacre in April deepened international worries of a slide into genocide.
"They attacked only six hours after the ceasefire came into effect," Aguer told Reuters, although he said the government's SPLA army was able to repulse both assaults.
The latest ceasefire was signed late on Friday and all fighting was supposed to stop 24 hours later.
In rival accusations, rebel military spokesman Lul Ruai Koang said the army launched attacks in Unity state and Upper Nile state, another oil producing region. He said shelling on Upper Nile rebel positions began a few hours before the ceasefire deadline but continued after it into Sunday morning.
"The latest violations of the agreement to resolve the crisis in South Sudan shows that Kiir is either insincere or not in control of his forces," he told Reuters.
Mediators had demanded Kiir and Machar meet for face-to-face talks in Ethiopia this time, rather than leave any ceasefire to negotiators, to ensure a personal commitment to making it hold.
Analysts have suggested in the past there was a risk troops on the ground might not always follow their commanders' orders in a conflict that has increasingly followed deep ethnic divisions, pitting Kiir's Dinka people against the Nuer of Machar.
There was no immediate independent verification of either report of fighting. An official from the U.N. mission in South Sudan had no immediate word about any violations that could threaten to extend a conflict that has already lasted about five months.
Securing independent confirmation of incidents via ropey communications across a poor country the size of Texas is often a slow process.
The United States and European Union states, which have been pressing hard for a deal, had welcomed Friday's agreement and called on both leaders to issue immediate orders for a halt to fighting.
Washington, which has already slapped sanctions on commanders from each side, warned of further steps if fighting continued. The EU also said it was considering punitive measures on those who committed rights abuses or blocked talks.
(Writing by Edmund Blair; Editing by Andrew Heavens)