Rebels in South Sudan took control of nearly all of a strategic city, even as the government and fighters agreed to hold talks for the first time.

South Sudan’s government has agreed at a meeting of East African leaders to end hostilities against rebels accused of trying to overthrow the young country’s regime, but the ceasefire was quickly thrown into doubt because the head of the rebellion was not invited.

Fighting has spread further along the Sudan-South Sudan border with 22 troops killed in a clash between soldiers from both countries.