The European parliament on Thursday urged Israel to conduct an impartial investigation into the prison death in February of Palestinian militant Arafat Jaradat.
The bloc's parliament passed a resolution calling "on the Israeli authorities promptly to open independent, impartial and transparent investigations into the circumstances of Mr Jaradat’s death."
In a resolution voted two days after a visit by Israeli President Shimon Peres, the European parliament reiterated its support for the Jewish state but urged it to respect the rule of law.
Jaradat's death in an Israeli prison last month sparked angry demonstrations across the West Bank in which dozens of Palestinians were injured in confrontations with Israeli forces.
Palestinian officials have accused Israeli interrogators of torturing the 30-year-old father of two to death. Israel says the cause of death has yet to be determined.