By Aaron Maasho
ADDIS ABABA, Aug 24 (Reuters) - A member of an East African regional body monitoring a ceasefire in South Sudan died of a heart attack after some monitors were detained by rebels to the north of the country, further complicating a peace process.
Ethiopia's Seyoum Mesfin, the chief mediator at the Inter Governmental Authority on Development (IGAD), which is trying to broker peace in South Sudan, said the rebels' action was a violation of the cessation of hostilities agreement signed by the two warring parties earlier this year.
Seyoum said the incident happened early on Sunday in the oil-producing Unity state, but he did not disclose the total number of those being held or their nationalities.
At least 10,000 people have been killed since fierce fighting erupted in December, pitting President Salva Kiir's government forces against supporters of Riek Machar, his former deputy and longtime rival.
Another IGAD official told Reuters the one who died was a South Sudanese national representing the government side.
IGAD has eight groups of monitors in flashpoint areas. Each of the eight teams comprises of up to six monitors.
Both the government and the rebel side have one representative in each group, IGAD officials said.
The monitors have been deployed to the capital Juba, where fighting first erupted, Malakal and Bentiu, both northern oil-producing areas in Unity state and Bor, scene of some of the heaviest fighting about 200 km (120 miles) north of Juba.
Peace talks between the government and rebels brokered by IGAD in Ethiopia's capital Addis Ababa have so far not produced results.
East African heads of state were scheduled to meet in the city later on Sunday in the latest bid to ramp up the pressure on both sides to end the conflict. (Editing by James Macharia and Stephen Powell)