NORTH BRUNSWICK, N.J., APRIL 24 -- A 7-year-old boy died today after he was swallowed by a sinkhole while playing outside an apartment complex.

About 100 rescuers worked more than seven hours to dig him out, but Kwame Sharif was dead on arrival at a local hospital, officials said.

The boy stuck his foot in a small hole in a courtyard of the North Brunswick Manor Apartments while playing with his twin brother Kwasi, when the ground gave way and he sank into a hole 8 feet deep and 2 feet wide.

When the child was located, Mayor Paul Matacera said, "His body was dry, but there was a couple of inches of water. . . . He was slumped down in the water."

Neighbor Gary Nelson said he and the boy's father tried to pull the child to safety but could not reach him.

"His father and I were the first on the scene, and his hands were in the air. He said, 'Daddy, get me out of here; there's snakes down here,' " said Nelson. "We tried to grab his hand and the ground started giving under him."

Rescuers pumped oxygen and heat into the hole in an effort to keep the boy alive, but, as one police officer said, "The boy was just down there too long. He was buried for seven hours."

Authorities said they did not know what caused the sinkhole, but a police officer said the earth may have collapsed because of heavy rains.