The targeted killing of Soleimani, a powerful figure among forces aligned with Iran throughout the Middle East, dramatically increased tensions in the region and caused U.S. outposts and personnel to brace for retaliatory attacks. The attack also upset global markets and sent oil prices shooting upward. The U.S. Embassy in Baghdad warned Americans in Iraq to leave “immediately.”

The Pentagon said that it will deploy 3,500 additional troops to the Middle East after Iran vowed to exact “severe revenge” on the United States for the drone strike that killed Soleimani early Friday near the Baghdad airport.

Iraqi militias allied with Iran had been harassing U.S. forces in Iraq in recent weeks, including an attack on a base that killed a U.S. contractor. The United States has said that Soleimani was killed as he was planning new attacks and that Trump ordered the attack.

Here are key points of what we know:

Soleimani was a towering figure who was key in training Iran’s proxies around the region, especially in Iraq.

• There has been mixed reaction across the Middle East, with some praising Soleimani but others blaming him for instability in the region.

• Reaction in the United States has also been mixed, mostly along party lines between Republicans and Democrats.

• The Pentagon’s top general defended the decision to kill Soleimani on Friday afternoon, saying Soleimani was planning a “campaign of violence” against Americans.