A Gaza Strip man who died early Monday after he was shot by Israeli forces as he approached the border fence with Israel was mentally ill, his family said.

Israeli forces shot 23-year-old Ahmad Nabhani as he crawled toward the border Sunday evening, partially concealed in a dried river bed, an Israeli military spokeswoman said. She said he ignored several warnings to stop. Nabhani later died of his wounds.

"He was sick — he had a mental illness," said Nabhani's brother Hazem, 27. He said his brother was being heavily medicated for depression and had approached the border fence three times previously. Each time, Israeli forces handed him back to Palestinian authorities, his brother said.

"My brother didn't understand anything. Sometimes you'd speak to him and he wouldn't understand. It is like he wasn't there."

Israeli forces frequently fire on people in the border area, because militants often use it to fire rockets at Israeli communities nearby. But occasionally Palestinian children and others who don't understand the dangers wander in.