MANILA, Philippines — A young girl waved a Barbie doll in the air while a boy licked an ice cream cone. Another girl casually finished a bottle of water while chatting with a classmate.

Dozens of children were taken hostage on a bus yesterday by a day-care center owner armed with grenades and guns, but the youngsters took the ordeal in stride, eating pizza, smiling, and waving from the windows throughout the day.

The crisis ended after 10 hours when 56-year-old civil engineer Jun Ducat, who staged the incident to denounce corruption and demand better lives for impoverished children, released the children, put the pin back in a grenade, and surrendered to police.

Jubilant parents were quickly reunited with their children as they filed off the bus clutching dolls, toys, and backpacks. Mr. Ducat was led to a waiting police car and driven away.

“I was afraid all day that the grenade may explode,” said Gerome Agabon, father of 5-year-old hostage Joanne.

Manila police district chief Danilo Abarzosa said Mr. Ducat would be charged with 32 counts of illegal detention and abduction — each count is punishable by up to 12 years in prison — along with illegal possession of explosives and firearms.

“I accept that I should be jailed because what I did was against the law,” Mr. Ducat said in an interview with the Associated Press shortly before the standoff ended.