Sudan could begin peace talks with eastern rebels in August, the top U.N. envoy in the country said on Thursday, adding he hoped for a full peace deal by the end of the year between the government and rebels from the western Darfur region, Reuters reported. But Jan Pronk said the declaration of principles (DOP) signed between Darfur rebels and the government on Tuesday in the Nigerian capital Abuja needed to be translated into action on the ground. He urged the rebel Sudan Liberation Army (SLA) to release 10 aid workers held hostage, and told the government to reprimand a military commander who was firing mortars over an aid agency's headquarters in the tense region of Golo in central Darfur. "(Eastern) talks could start sometime in August," Pronk told reporters in Khartoum. He declined to give further details. "Peace before the end of this year," he said of Darfur, "that's the objective." --More 2339 Local Time 2039 GMT