JUBA - South Sudan's civil war entered its ninth month Friday with rebels and government troops engaged in heavy battles, diplomats said, days after UN warnings of sanctions if the conflict continues.
Fighting was reported around the town of Bentiu, capital of the northern oil state of Unity, as well as in Jonglei state.
Rebel spokesman Lul Ruai Koang claimed it was the start of a "long awaited government offensive", reporting clashes to the east and south of Bentiu.
He also said there was fighting in the remote village of Ayod in the eastern Jonglei state, one of the areas hardest hit by a growing hunger crisis.
Aid workers also reported heavy shooting around Bentiu.
The army was not immediately available for comment.
The British ambassador in Juba, Ian Hughes, said the reports of fighting was "disappointing", coming just three days after UN Security Council envoys warned both the government and rebel leaders of "consequences" on a visit to the troubled nation.
"The situation there is desperate enough already," Hughes said. "Leaders need to control their fighters." UN envoys met with President Salva Kiir in Juba and also spoke with rebel chief Riek Machar, urging them to stick to peace after three failed ceasefire deals.
Thousands of people have been killed and more than 1.5 million have fled civil war sparked by a power struggle between Kiir and his sacked deputy Machar, with battles between government troops, mutinous soldiers and ragtag militia forces divided by tribe.
The United Nations has said the food crisis is the "worst in the world", with aid workers warning of famine within weeks if conflict continues.
The United States and the European Union have already imposed penalties on three senior South Sudanese army commanders from the government and opposition, while nations in the regional bloc IGAD have suggested they could follow suit if progress was not made.
East African leaders from the Intergovernmental Authority on Development are due to hold talks at the weekend in the Ethiopian capital to discuss the war in South Sudan.