A 180kg (400-pound) gorilla has escaped from its enclosure and run amok at Rotterdam zoo in the Netherlands.
Witnesses reported seeing the gorilla, a dominant male, climb the enclosure's wall and apparently bite a woman, as well as injuring three other people.
The zoo was evacuated as the gorilla was subdued by a sedative dart after it sought refuge inside a zoo building.
The Diergaarde Blijdorp Zoo, which was packed with visitors on a holiday weekend, later reopened.
Many people in the Netherlands were taking advantage of a national holiday to make a long weekend.
Somehow Bokito escaped from his enclosure
The 11-year-old gorilla, called Bokito, managed to climb a high wall to escape from his enclosure.
"He got over the moat, which in itself is remarkable because gorillas can't swim," zoo director Ton Dorrestijn told reporters.
Visitors then described scenes of panic, as families ran screaming from the animal.
"I saw the beast running through the park with a woman behind him, him grabbing her forearm," eyewitness Robert De Jonge told NOS radio.
"He bit her, or I think he bit her, because when he stood up his mouth was covered in blood," Mr De Jonge said.
Some visitors tried to barricade themselves in a restaurant, but Bokito smashed part of a door and gained entry. He was eventually trapped there by zoo staff and tranquilised.
None of the injured was thought to be in a serious condition.