On Sunday, tens of thousands of mourners clad in black filled the streets of Mashhad and Ahvaz to pay their respects to Qassem Soleimani, Iran’s powerful Quds Force commander who was assassinated by a U.S. airstrike in Iraq.

Soleimani’s remains were flown to the southwestern Iranian city of Ahvaz two days after his killing, triggered what is perhaps the most dramatic escalation of tensions in the Middle East since the U.S. invasion of Iraq.

Several others were also killed in Friday’s strike on a convoy at Baghdad airport, including the Iranian-backed Iraqi militia leader Abu Mahdi al-Muhandis—who commanded the PMU militia forces.

In live footage aired on Iranian state television, tens of thousands of mourners marched through Ahvaz holding up portraits of Soleimani, seen as a hero for his role in the Iran-Iraq war in the 1980s and for shaping events throughout the Middle East in his role as chief of the Iranian Revolutionary Guard Corps’s (IRGC) overseas forces.

The footage showed crowds thronging Mollavi Square with flags in green, white and red – depicting the blood of “martyrs” – men and women weeping as they beat their chests to the sound of chants.

Authorities took Soleimani’s remains to the holy city of Mashhad later on Sunday. This was followed by more public processions in both Tehran and the holy city of Qom on Monday. From there, his remains are set to be taken to his hometown of Kerman for burial on Tuesday.

The current Iran-U.S. crisis can be traced to the Trump administration’s decision, in 2018, to pull out of the Iran nuclear deal. Commonly referred to as the JCPOA or Joint Comprehensive Plan of Action, the nuclear deal was signed in 2015 between the leaders of Iran, the US and other world powers, despite the protestations of hardliners in the US, Iran, and Israel. The accord is likely to further unravel now that Iran has taken steps to walk away from it, as a result of this past week’s incident together with the U.S.’s withdrawal and re-imposition of punishing sanctions.

How events will pan out from here, remains unclear. However, the sense of anger within the ruling class of Iran is palpable, and it seems likely that there could be a retaliation of some form if the recent statements from both Iran’s Supreme Leader and the country’s President are anything to go by following Soleimani’s assassination, Iran’s Supreme Leader Ayatollah Ali Khamenei warned of “harsh revenge” as he called for three days of national mourning. Meanwhile, Iranian President Hassan Rouhani said Tehran’s response to the killing would be long and drawn out.

Judging by Tehran’s proven track record in terms of its ability to mobilize proxies in countries like Iraq, Syria, Lebanon, and Yemen, these remarks should be taken seriously. Immediate attention should be paid to potential targets within Iraq, where the U.S. has a sizeable military and civilian presence. Despite US President Donald Trump’s recent threats to hit 52 Iranian sites & very fast and very hard & if Iran was to target U.S. citizens or assets, the recent actions, and statements by the American president risk endangering the lives of those who have no blame whatsoever in the recent escalation of violence that we have witnessed in recent days, in Iraq.

In fact, the potential endangerment of civilian and military persons should figure more prominently in the minds of Iranian and American decision-makers, especially in such a delicate period in U.S.-Iranian relations. The bellicose rhetoric and the military maneuvers by actors involved across that great divide between both countries has led to the situation that we find ourselves in at the moment. Each side is responding in its own way to the actions of the other. Some of it has been heavy-handed, ruthless, costly, and unfortunately at the expense of stability within Iraq and the Middle East. The dispatching of 3,000 American troops to Kuwait—the latest in a series of deployments in the region in recent months—together with the recent launching of rockets American targets in Baghdad’s Green Zone and other locations near the capital, only serves to illustrate that point.