Ahmed Barhoum, 22, a volunteer guard at the Rafah refugee camp, was hit in the head by a bullet early on Wednesday.
Palestinians at the camp said they also heard an explosion. The Israeli military said it did not know of the incident, but over 20 Palestinians have been killed since a ceasefire was announced on 8 February, most of them children.
Meanwhile, hundreds of young protesters flooded Israeli courtrooms on Tuesday after blocking dozens of highways a day before.
Extra judges were brought into courtrooms to handle hearings for more than 300 protesters, most of them in their teens and early 20s, detained while blocking highways with burning tires and their own bodies.
Police agreed to release about 130 with a ban on similar protests for 60 days.
Supporters of the Israeli protesters, most of them teenagers with large skullcaps and ritual fringes identifying them as Orthodox Jews, sang and danced outside the coutrooms on Tuesday, encouraging their friends as they were taken inside, many in handcuffs.
The protest ban would expire in mid-July, just as the activists move into high gear in their drive to scuttle the pullout.
Organisers called the road blocking exercise a success, noting that they tied up thousands of police. In August, they believe, diverting such large numbers from Gaza would cause cancelation of the evacuation.
Security officials say they have contingency plans to meet the challenge. Police Commissioner Moshe Karadi said most of the protesters would be charged.
"They did not accomplish their goal to disrupt life in Israel," he told reporters on Tuesday, "but from time to time they will succeed."
The planned evacuation of all 21 illegal Gaza settlements and four in the West Bank would be the first time Israel has removed colonies from those areas after nearly four decades of construction and expansion.
The change is especially hard to swallow for Orthodox Jewish ideologues who see the West Bank and Gaza as part of the land promised to Jews in the Bible, and reject any pullout on religious and security grounds.