Since late last year, various Iranian-backed groups have struck U.S. troop positions in Iraq and Syria, tried to bomb merchant vessels in Middle East waterways, and aimed rockets at the U.S. Embassy in Baghdad.
The U.S. has responded by shooting down rockets, sinking enemy boats in the Red Sea and authorizing strikes on militant group assets and individuals in Syria and Iraq.
As Israel continues to prosecute its devastating war against Hamas in the Gaza Strip, there's growing concern that the tit-for-tat exchanges with Iranian proxies outside the war zone could expand the conflict.
An Israeli airstrike in southern Lebanon on Monday killed a top Hezbollah commander, in the latest instance of the war stretching beyond the Gaza Strip.
While there are plenty of unknowns at play, including whether and how the U.S. plans to further respond to provocations, officials worry the aggression could potentially draw the U.S. into another Middle East war, an outcome Washington is desperate to avoid.
Here are where the biggest potential powder keg moments are taking place.
Houthi attacks on commercial ships in Red Sea and Gulf of Aden
Since Nov. 18, Iran-backed Houthi militants in Yemen have launched numerous exploding drones and missiles at military and civilian ships, also attempting to seize the latter, in protest of Israel’s military operations in the Gaza Strip.
There have now been more than 26 Houthi attacks on merchant vessels transiting the southern Red Sea and Gulf of Aden, with no signs of letting up.
The bombardments have successfully disrupted international shipping and supply lines, with Maersk and other major shippers suspending their transits through the waterways.
The U.S. has attempted to mitigate the aggressions via Operation Prosperity Guardian, launched Dec. 18. The now 22-nation maritime task force is meant to defend ships from Houthi attacks in the region.
But the militant group didn’t appear to be fazed when shortly thereafter, on Dec. 31, U.S. and Houthi forces directly clashed when militants aboard four small boats attempted to seize a Singapore-flagged container ship. The U.S. responded, sinking three of the four boats, killing 10 fighters.
In a seemingly final warning issued last week, the United States along with 13 ally and partner nations told the Houthis to stop the attacks, or else.
“The Houthis will bear the responsibility of the consequences should they continue to threaten lives, the global economy, and free flow of commerce in the region’s critical waterways,” the group of nations said, according to the joint statement released by the White House.
The Pentagon has so far declined to say what such consequences would entail, but defense officials have reportedly compiled a list of potential targets to strike in Yemen, including Houthi munitions storage facilities, radars and missile and drone launch sites.
Iranian proxies strike Syria, Iraq bases housing American troops
Since mid-October, the U.S. military has come under attack more than 100 times in Iraq and Syria by Iranian proxies launching rockets and one-way attack drones at troop positions, minorly injuring dozens of service members and critically injuring several others.
The United States has 2,500 troops in Iraq and 900 in neighboring Syria focused on preventing a resurgence of Islamic State militants, a force that had kept a relatively low profile before the recent wave of bombardments.
The U.S. has responded to the attacks with at least six separate retaliatory strikes, three in Syria and three in Iraq.
The Syria strikes fell on Oct. 26, Nov. 8 and Nov. 12, while those in Iraq took place on Nov. 20 and 21, and Dec. 25.
The latest, a bombing of three locations in Iraq late Christmas Day, followed a drone attack less than 13 hours earlier by Iran-aligned militants at a U.S. base in Iraq's Erbil. That strike left one U.S. service member in critical condition and wounded two other U.S. personnel.
The same American base has been a frequent target of militant attacks, including an Oct. 26 incident when a drone hit the barracks there but failed to detonate.
“Let me be clear — the President and I will not hesitate to take necessary action to defend the United States, our troops, and our interests. There is no higher priority,” Defense Secretary Lloyd Austin said in the statement at the time.
“While we do not seek to escalate conflict in the region, we are committed and fully prepared to take further necessary measures to protect our people and our facilities.”
High-profile attacks in Baghdad
Two attacks over the past month have been carried out by each side in Iraq’s capital: The U.S. Embassy compound came under mortar fire last month, and last week a U.S. strike killed an Iraqi militia leader in the city.
For the first time in more than a year, the U.S. Embassy in Baghdad on Dec. 8 came under attack when approximately seven mortar rounds landed in its compound.
No group claimed responsibility for the incident — one of the largest recent attacks against the embassy — though initial evidence pointed to Iran-aligned militias.
There was minor damage to embassy facilities and no injuries, but the attack further strained tensions between the U.S. and Iraq.
In an unrelated event, the U.S. last Thursday targeted and killed Jawad Kazim al-Jawari, or Abu Taqwa, the leader of the Iranian-backed militia group Harakat Hezbollah al-Nujaba (HHN), after he landed near a security headquarters in Baghdad.
The HHN — part of the Popular Mobilization Forces, a network of Iranian proxy groups and militias in Iraq — has been responsible for numerous drone and missile strikes on bases that house U.S. forces in the region.
Abu Taqwa had been “actively involved in planning and carrying out attacks against American personnel,” Pentagon spokesperson Maj. Gen. Pat Ryder said Thursday.
But the strike angered Iraqi officials as the U.S. action did not appear to be in coordination with Baghdad, though the Pentagon has said they notified the country's government prior to the action.
Prime Minister Mohammed Shia al-Sudani, who was elected with the backing of a coalition of Iran-linked parties, on Friday announced he would begin discussions to remove the U.S. military presence in his country.
He claimed the American strike violated the equal sovereignty agreement between the two countries, under which U.S. troops are allowed to be based in Iraq states.
He also condemned the U.S. for the strike, noting that the Popular Mobilization Forces are “an official presence affiliated with the state.”
The Pentagon has countered that while the U.S. is in Iraq at the invitation of the Iraqi government to defeat the Islamic State terrorist group, its forces will take action to protect themselves.
Ryder on Monday said he was not aware of any notifications by the Iraqi government to the Pentagon regarding the removal of U.S. forces from the country.