WASHINGTON (Reuters) — President Donald Trump is weighing a strategy that could allow more aggressive U.S. responses to Iran‘s forces, its Shi’ite Muslim proxies in Iraq and Syria, and its support for militant groups, according to six current and former U.S. 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 on Friday, the sources said.

It could be agreed and made public before the end of September, two of the sources said. All of the sources are familiar with the draft and requested anonymity because Trump has yet to act on it.

In contrast to detailed instructions handed down by President Barack Obama and some of his predecessors, Trump is expected to set broad strategic objectives and goals for U.S. policy but leave it to U.S. military commanders, diplomats, and other U.S. officials to implement the plan, said a senior administration official.