Hamas’ armed al-Qassam Brigades said on Saturday that some hostages were killed in Israel’s hostage freeing operation at al-Nuseirat refugee camp and nearby areas in central Gaza.

Israel, “by committing horrific massacres, was able to free some its hostages, yet it killed some others during the operation,” al-Qassam Brigades’ spokesperson, Abu Ubaida, said in a statement on his Telegram channel.

Israeli forces rescued four hostages held by Hamas since October in a raid in Gaza on Saturday while over 200 Palestinians were killed in airstrikes in the same area, according to Hamas officials, in one of the bloodiest Israeli assaults of the war.

It was not immediately clear if the hostage rescue and the Israeli air assault were part of the same operation but both took place in Gaza’s al-Nuseirat, a densely built-up and often embattled area in the eight-month-old war between Israel and Hamas, the Palestinian territory’s ruling Islamist group.

Saturday’s “operation will pose a great danger to the enemy hostages and will negatively impact their conditions and lives,” Abu Ubaida added.