Jerusalem (CNN) -- A second Palestinian teenager died Thursday from injuries he suffered during clashes with Israeli security forces a day earlier, the official Palestinian news agency said.
Naji Balbisi, 19, was detained for hours by Israeli soldiers before he was turned over to an ambulance, the WAFA news agency said.
On Wednesday, Balbisi's 17-year-old cousin, Amer al-Najjar, was killed when Palestinians clashed with Israeli forces in the West Bank city of Tulkarem, WAFA said.
The Israeli military said it will check into the report of the latest fatality.
An Israeli military spokesman said several Palestinians attacked a checkpoint with firebombs Wednesday, prompting soldiers to open fire.
"Over the course of (Wednesday), Palestinians threw over 50 firebombs in an illegal riot," a military spokesman said. "The IDF (Israel Defense Forces) responded, and after searching the premises, they only found one body."
The mayor of Anabta, in the West Bank, said a handful of Palestinian youths went to an Israeli guard tower and threw stones. The mayor said Israeli forces responded by opening fire.
The deaths fueled tensions between Palestinians and Israelis as Palestinians prepared for the Thursday funeral of a prisoner who died in Israeli custody.
What's started the recent turmoil?
Clashes erupted in Hebron, Gaza, Ramallah and other cities across the Palestinian territories on Tuesday after retired Gen. Maysara Abu Hamdiya, a well-known Palestinian prisoner, died of cancer in Israeli custody on Tuesday.
The death sparked outrage among Palestinian groups who accuse Israel of denying Hamdiya treatment.
Hamdiya, 64, had been held in Israeli prisons since 2002 and was serving a life sentence for alleged involvement in an attempt to bomb a Jerusalem cafe.
He was admitted to an Israeli hospital last week because of his deteriorating health, according to the Palestinian Authority's government media center.