According to the Global Times and other reports, the US military command has announced that it has launched large-scale air strikes on seven military bases in the Middle East, and US bombers and fighter jets have dropped more than 125 precision munitions on at least 85 Iranian targets, which is in retaliation for the attack on the US military base in the "Tower 22" that resulted in dozens of US troops. 
Tower 22 "The attack on the base cost the U.S. military a lot) According to the U.S. military statement, the targets were distributed in Iraq and Syria, and the targets were "Iranian Revolutionary Guard Corps and pro-Iranian militia targets." The US military stressed that the airstrikes destroyed a large number of military facilities, including missiles, rockets, and unmanned aerial vehicles, as well as ammunition depots and command and intelligence centers. 
There is a detail here, that is, the U.S. military dispatched B-1 bombers from the United States to carry out a "transatlantic air strike" across the ocean, and the bombers "flew directly to the Middle East" from the United States, and received technical support such as in-flight refueling in the middle. This kind of intentional or unintentional action seems redundant, but in fact it is also flexing its muscles, because US bombers can drop nuclear bombs, and taking off and dropping long-range ammunition on the mainland is already a threatening move. 
Data map: B-1 bomber fires flares) However, although the US air strikes are huge, they avoid direct strikes on Iran and only hit regional targets in Syria and Iraq. Moreover, because Biden has been shouting "revenge" for a long time, the Iranian side has also been prepared, and Khamenei has already issued a death order in advance, asking all forces in Iran to endure it and not to break out into a frontal conflict with the US military. (Khamenei).
The U.S. airstrikes have also sparked outrage in Iraq, which accuses the U.S. of violating sovereignty, a position supported by the Houthis. However, according to **, the U.S. military informed Iraq of its plans in advance before the airstrikes, which may also lead to Iran being informed of the U.S. military's plan of action in advance. This scene is reminiscent of the fact that after Soleimani was "beheaded" by the US military in Iraq in 2020, when Iran launched a missile air strike on the US military station in Iraq, it also notified Iraq in advance, which is actually equivalent to giving the US military time to avoid danger. 
The Soleimani affair also almost triggered a direct conflict between the United States and Iran).
It is clear that there is some kind of tacit understanding between the United States and Iran, and both Washington and Tehran want to do everything possible to avoid the outbreak of direct conflict. In fact, the White House has identified the Iraqi militia as the "attackers" in advance, and Biden has stressed that he "does not want to go to war with Iran", and the United States has even told the air strike plan in advance, and it is expected that the air strikes will "last for several days", and it will also depend on the weather forecast. (Biden attends the handover ceremony of the remains of U.S. soldiers).
The United States is well aware of the consequences of a direct attack on Iran, and although Iran now wants to avoid war, the attitude of Iran's Revolutionary Guard Corps and military is very tough, and the commander-in-chief of the Revolutionary Guard Corps, Hussein Salami, has publicly warned the United States that any threat will be reciprocated. Iran is powerful, and its missile forces are capable of directly deterring US military stations in the Middle East, as well as striking Israel. (Commander-in-Chief of the Iranian Revolutionary Guard Corps, Hossein Salami).
Moreover, Iran has many allies in the Middle East, such as the Houthis and the Iraqi militia, which are actually Iran's small partners.