Twenty-eight prisoners escaped from a prison in Dendermonde in the Belgian province of East Flanders, the Belga news agency reported Saturday. Police launched a large search operation, which included the use of a helicopter, and seven of the prisoners who escaped overnight had been recaptured, according to dpa. Two prisoners from an Eastern European gang of thieves broke out of their cells early Saturday and took several warders hostage. Using the warders' keys they set 26 more prisoners free. Nobody was injured in the escape, the authorities said.