Israeli Prime Minister Benjamin Netanyahu faced pushback from the head of the military over his proposal to seize remaining areas of Gaza that it doesn’t already control during a tense three-hour meeting, Reuters reports, citing three unnamed Israeli officials.

The military chief of staff, Eyal Zamir, warned the prime minister that taking the rest of Gaza could trap the military in the territory, which it withdrew from two decades ago, and could lead to harm to the hostages being held there, the sources briefed on the meeting said.

The UN has called reports about a possible expansion of Israel’s military operations in Gaza “deeply alarming” if true.

Netanyahu, who favours an expansion of military operations, told Zamir that so far the military had failed to bring about the release of the hostages, the officials said, speaking on the condition of anonymity.

Diplomatic negotiations have secured the release of most hostages freed so far. A fourth source said that the prime minister intended to expand military operations in Gaza to put pressure on Hamas.