NAIROBI (Reuters) - South Sudan's government carried out a helicopter gunship attack on rebel positions days after committing to a peace deal, mediators said in the first confirmation of ceasefire violations since the pact was struck.
The world's youngest country descended into civil war in December 2013 when a row between President Salva Kiir and former deputy Riek Machar spiraled into fighting, reopening ethnic fault lines between Kiir's Dinka and his foe's Nuer people.
The United States and other Western supporters accuse Kiir and Machar of squandering goodwill after South Sudan's 2011 independence and hindering development in an oil-producing nation with almost no tarmac roads and heavily reliant on aid.
Under pressure from neighboring countries and the looming possibility of sanctions, Machar signed the peace deal on Aug. 17 and Kiir 10 days later, though both sides were quick to accuse each other of further attacks.
In a report, the regional bloc of East African states known as IGAD said its monitors had witnessed government "helicopter gunships flying towards and engaging the SPLM/A(IO) forces on the west bank of the Nile", referring to the rebels.
The monitors witnessed the attacks took place on Sept. 2 in the Lelo, Awarajwok and Detand areas of oil-producing Upper Nile state in the country's east, the report said.
It recommended that IGAD special envoys condemn the government forces' action and "insist that they abide by their obligations to the (ceasefire deal) especially after signing the recent agreement on the resolution of the conflict".
Machar's rebels also violated the ceasefire by launching attacks in Unity state on Aug. 23, monitors said, although those incidents occurred before Kiir signed the peace agreement.
Increasing pressure on both sides to desist from bloodshed, the United States proposed sanctions this week on South Sudan's army chief and a rebel commander, but some U.N. Security Council members requested that the move be put on hold.
The Security Council blacklisted six generals -- three on the government side, three fighting for the rebels -- in July, the first people connected to the conflict to be subjected to a global asset freeze and travel ban.
Monitors documented 48 violations by Sept. 9 of the cessation of hostilities agreement signed on Feb. 8 last year, of which 28 were committed by rebel forces and the rest by the government troops.
Reporting by Aaron Maasho; Editing by George Obulutsa and Mark Heinrich