The Pentagon is deploying about 2,000 more troops and military hardware to Saudi Arabia to combat Iranian aggression.

Tensions between Saudi Arabia and Iran have escalated in recent months, most notably when Iran bombed Saudi oil refineries in September. The Pentagon’s latest deployment to the region is the third since July and it is the largest, according to the Wall Street Journal.

The Pentagon is sending three missile defense systems and two squadrons of jet fighters along with the troops. U.S. lawmakers are growing increasingly resistant to American support for Saudi Arabia in the escalating Middle East conflict.

The troops will join 700 other soldiers already stationed in Saudi Arabia.

Iran has grown increasingly aggressive since President Trump withdrew the United States from the Iran nuclear deal negotiated under President Barack Obama. Trump withdrew from the agreement and reinstituted U.S. sanctions that have squeezed the petro-state. Iran has launched several attacks into the Strait of Hormuz, a key shipping lane, since Trump's action, even shooting down a U.S. drone.

Trump announced on Sunday that he had ordered several dozen troops out of northern Syria in an effort to end the "endless wars" in the Middle East. The move made way for Turkish forces to launch an assault on Kurdish forces that had aided the U.S. in the fight against the Islamic State.