US retaliation, when it came, was broad and deep, and telegraphed five days in advance.

The White House, the Pentagon and state department had spent the best part of a week talking about the response to Sunday’s drone attack on a US base in northern Jordan, which killed three Americans and wounded more than 30.

They warned that retaliation against the suspects, primary among those the Iran-backed Kataib Hezbollah militia, would be “multi-tiered” and continue over many days, but when the opening salvo came in the early hours of Saturday Middle Eastern time, it still caused some surprise in its range and scale.

According to US Central Command, 85 targets were hit in seven facilities, four in Syria and three in Iraq, with more than 125 precision munitions, using a mix of drones and long range B1 bombers flying from US territory in a demonstration of the reach of the US air force.

“Tonight’s strikes in western Iraq eastern Syria are FAR bigger than any action undertaken before against Iran’s proxies – huge secondary explosions on both sides of the border suggest big rocket/missile depots have been hit,” Charles Lister, senior fellow of the Middle East Institute, said on the social media platform X.

Joe Biden said the targets were facilities used by Iran’s Islamic Revolutionary Guard Corps (IRGC) and “affiliated militia”, and he made clear that it was just the beginning. The full response for the attack on the Tower 22 base would “continue at times and places of our choosing”.

The limits of the response were as clear as its scale. As expected, no targets were hit on Iranian territory, and senior administration officials made clear Iran was out of bounds for any future sorties as well.

“The goal here is to get these attacks to stop. We’re not looking for a war with Iran,” John Kirby, the national security spokesperson, said.

Meanwhile, the five intervening days since the Tower 22 attack had reportedly given time for the withdrawal of key IRGC officers. The Pentagon said that the timing of the strikes was determined by the weather. The planners had waited for the skies to clear to be absolutely certain of their targets so that civilian casualties would be minimised.

As for the question of whether the delay had allowed the IRGC to pull its people out of danger, Lt Gen Sims, the director of operations of the Joint Staff, pointed out that the militias attacking US targets would have scattered as soon as their weapons had been fired, so the number of days’ pause did not make much difference. The impact of the overnight strikes, Gen Sims said, was to significantly degrade the IRGC arms stockpiles.

Overall, the US response was calibrated to minimise the risk of a direct US-Iran conflict, while maximising the destruction of weaponry Iran has stockpiled in Syria and Iraq.

It is notable that three of the targeted facilities were in Iraq. There had been some speculation that the US planners might avoid that, as Baghdad’s permission for a continued US troop presence involved in pursuing Islamic State is under review after a prior US strike on Iraqi soil.

The White House said that the US informed Baghdad ahead of the strikes; nonetheless an Iraqi army spokesperson said they constituted “an assault on Iraq’s sovereignty and an insult to the government”.

While risking a war with Iran was clearly a red line in the planning of this response, the risk of further complicating the relationship with Baghdad was clearly not a barrier. It is the US assessment that the Iraqi government is ultimately reliant on American soldiers to keep Islamic State at bay.