United Nations Secretary-General Antonio Guterres has invoked rarely used Article 99 of the founding UN Charter to push for a ceasefire in a letter to the Security Council.

The United States and ally Israel oppose a ceasefire because they believe it would only benefit Hamas, Reuters reports.

Israel’s UN Ambassador Gilad Erdan denounced Guterres’ move: “The Secretary-General’s call for a ceasefire is actually a call to keep Hamas’ reign of terror in Gaza.”