U.S. President Donald Trump is weighing a strategy that could allow more aggressive U.S. responses to Iran’s forces, its Shiite proxies in Iraq and Syria, and its support for militant groups, six current and former U.S. officials told Reuters on Monday.

According to the officials, the proposal was prepared by Defense Secretary Jim Mattis, Secretary of State Rex Tillerson, national security adviser H.R. McMaster and other top officials, and presented to Trump at a National Security Council meeting this past Friday.