Israel has been facing widespread criticism after launching a major offensive in the occupied West Bank early Monday. The operation saw hundreds of troops deployed in an incursion that resembled the broad attacks carried out during the second Palestinian uprising two decades ago.

Palestinian health officials reported at least eight Palestinians were killed and 50 wounded, some critically. In response to the violence, the White House said it was monitoring the situation closely and supports Israel’s security and right to defend its people against militant groups.

The United Nations also expressed deep concern, with Secretary-General Antonio Guterres urging all military operations to be conducted with respect for international humanitarian law. The Israeli army said it had uncovered three weapons-making facilities, confiscated hundreds of explosives and shot two Palestinian gunmen during shootouts.

Reports indicate that at least 3,000 Palestinians have left the Jenin refugee camp after the incursion. Foreign Minister Eli Cohen accused Iran of being behind the violence by funding Palestinian militant groups, something the Palestinian side rejects. Islamic Jihad, a militant group with a large presence in Jenin, threatened to launch attacks from its Gaza Strip stronghold if the fighting dragged on.

Lebanon’s militant Hezbollah group also condemned the attacks, while vowing Palestinians have “many alternatives and means that will make the enemy regret its acts.”