Divers were searching the East River Saturday for a 13-year-old boy who jumped in to prove to his friends that he could do it, and then disappeared, police and a relative said.

Witnesses called 911 around 4:30 p.m. Friday to report that the child had gone into the water at East 6th Street and FDR Drive, but not come out, police said.

Devina Glover, the child’s cousin, identified him as Kavion Brown.

A police spokesman said cops believed Kavion may have been trying to prove himself to his friends, saying, “Look what I can do” when he went into the river.

He was treading water when he was swept away by the current, authorities said.

Glover said the boy’s family is keeping vigil nearby at home and didn’t open their door when she knocked.

“They refused to open it,” she said, saying they may be trying to protect his younger siblings. “I don’t know if it’s because they haven’t found him yet.”

She said Kavion is an outgoing kid who “loved to play basketball” and had just made the team at the Lower East Side Preparatory School, where he’s a freshman.

Divers began searching Friday but had to stop because of inclement weather. They resumed their search when the rain stopped on Saturday afternoon, police said.

Foul play is not suspected, cops said.

Glover said she’s staying by the river.

“I’m just very uneasy at this point, but I have to be here, just trying to keep the faith and staying out here to see if they recover him,” she said.