Tensions were already high in oil-producing Sudan which is gearing up for presidential, parliamentary and state governor elections in April.
Saturday's attack follows an assault by the rebel Sudan Liberation Army (SLA) on the government garrison town Golo in Jabel Marra last Wednesday after days of government bombardment of rebel positions in Sudan's remote west.
"The government attacked our areas in the market area of Furug," SLA commander Ibrahim el-Helwu told Reuters. "This is a heavily populated area," he added.
The army spokesman's office was not immediately available to comment and the U.N.-African Union peacekeepers (UNAMID) said they were checking the reports.
"All the areas under the control of SLA (Abdel Wahed)...are a no-go area for us," UNAMID spokesman Noureddine Mezni said.
The rebels accuse the mission of working too closely with Khartoum and refuse to allow them to enter their areas.
The International Criminal Court (ICC) issued an arrest warrant for President Omar Hassan al-Bashir in 2009 for war crimes during a brutal counter-insurgency campaign in Sudan's west after rebels took up arms in 2003 demanding more autonomy.
Darfur's fighting sparked a humanitarian crisis which the United Nations estimates has claimed 300,000 lives and driven more than 2 million from their homes.
Fighting has largely subsided since the early battles, but sporadic clashes have since pushed rebels out of the main towns and into the vast swathes of arid countryside.
- Reuters - Thomson Reuters Foundation
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