Refugees in Sudan's troubled Darfur region have freed all of the 34 aid workers they had earlier seized.
More than 2m Darfur people have fled their homes
It appears the refugees were demanding the release of one of their leaders arrested by police at the weekend.
The kidnappings took place on Sunday at the Kalma camp - the largest camp in Darfur, housing almost 90,000 people.
Some 2m people have been forced from their homes since fighting between Darfur's black African rebels and Arab militias began early in 2003.
Workers from three different agencies were seized - two Sudanese organisations and one from the United States.
Five aid workers from the government water and sanitation agency were the last to be released on Tuesday.
Scared to return
Our correspondent says that after spending two-and-a-half years in refugee camps, a social order has been rebuilt, with community leaders at their head.
These men hold a tight grip over the refugee population, often profiting from the distribution of food aid and obstructing attempts by agencies to count the population, our correspondent says.
Our correspondent says there have been other angry and hostile reactions to police operations in refugee camps but this is the largest-scale incident of hostage-taking.
Many refugees are too scared to return home as the violence continues.
Earlier this month, the UN said it was pulling out all non-essential staff from West Darfur due to an upsurge in fighting.
In the last few weeks, displaced people have been attacked and killed by pro-government militiamen even in refugee camps.
The government has denied claims that it backs the Janjaweed militia, accused of widespread atrocities.
Rebels have kidnapped African Union peacekeepers and West Darfur's aid workers have been regularly targeted on its roads.