Iran’s defense minister, Brig. Gen. Amir Hatami, added that the attack would be met with a “crushing” response. Foreign Minister Mohammad Javad Zarif called the strike an “act of international terrorism” and, in a message on Twitter, said the United States “bears responsibility for all consequences of its rogue adventurism.”…

In a statement, Iraqi Prime Minister Adel Abdul Mahdi condemned the U.S. “assassination,” adding that the killing of the Iraqi militia leader was an act of aggression against Iraq and a breach of the conditions under which American forces operate in the country…

Ilan Goldenberg, who worked on Middle East issues during the Obama administration, characterized the move as a “massive game changer” in the region.

“Iran will seek revenge. It may escalate in Iraq, Lebanon, the gulf or elsewhere. It may attempt to target senior U.S. officials,” said Goldenberg, now a scholar with the Center for a New American Security. “Unfortunately, I highly doubt the Trump administration has thought out the next step or knows what to do now to avoid a regional war.”