A report on Monday claimed that U.S. intelligence has determined that Syrian President Bashar al-Assad has already made a decision to use chemical weapons against enemy positions in Idlib as his forces, combined with Russian airpower, attack the last rebel stronghold following seven years of civil war.
The Wall Street Journal [source], citing unnamed intelligence sources, even noted the type of gas Assad has allegedly chosen: Chlorine gas, which was first used in World War I and has the effect of an asphyxiation compound.
In addition, according to sources who spoke to the WSJ, President Donald Trump has also reportedly threatened to intervene militarily with a massive attack against the Assad regime if he uses gas and other tactics that result in a massacre. U.S. officials and diplomats are concerned about the extensive loss of life among the civilian population, especially.
There are believed to be about 3 million people in and around Idlib, which is an important agricultural region for Syrian. There is estimated to be about 70,000 anti-Assad regime fighters there, which Damascus considers to be terrorists.
Thus far, international diplomatic efforts to persuade Syria, Russia, and Iran from averting a major offensive have failed as all three sense that the rebel faction is on the verge of defeat after trying for years to forcefully remove Assad from power. Both Russia and Syria have increased air attacks and thousands of civilians have been evacuated to parts of Syria controlled by the government.
The Pentagon is currently drawing up military options for the president, but he has not yet decided on a course of action or even what would trigger a response beyond the use of poison gas.