Iran is bracing for a retaliatory Israeli attack on its territory or proxies, as the U.S. and European nations press Israel for a response that avoids an escalation in tensions caused by Tehran’s weekend missile and drone assault.

Iran said Wednesday it was readying its air force for strikes and its navy would begin escorting commercial Iranian ships in the Red Sea. Tehran also has begun evacuating personnel from sites in Syria where its Islamic Revolutionary Guard Corps has a large presence, Syrian and Iranian officials and advisers said.

The IRGC and Iran-backed militant group Hezbollah have reduced the presence of their senior officers in Syria while midranking officers are shifting from their original locations in the country, Syrian security officials said.

The Biden administration is encouraging Israel not to retaliate and to instead be satisfied that a U.S.-brokered alliance including Israel and Arab nations successfully repelled Iran’s Saturday assault, which included more than 300 attack drones and cruise and ballistic missiles. British and German foreign ministers were in Israel Wednesday to reinforce that message of de-escalation.

Israel has said it intends to respond, but officials are still undecided on the nature of the retaliation.

The shape of its response has the potential to expand Israel’s conflict in Gaza with Tehran-backed Palestinian group Hamas into a wider regional war, an outcome most sides appear eager to avoid, though fears are growing that Israel and Iran could misinterpret each other’s intentions.

To encourage Israel to limit its response, the White House said Tuesday it would impose a series of economic sanctions on Iran, including on the IRGC and its missile and drone programs. Other sanctions could target its oil industry and its ability to raise government revenues.

In a sign Israel is considering the U.S. and its allies’ message, Israeli officials assured Gulf states and other Arab countries on Monday that its response to Iran’s attack wouldn’t endanger their security and would likely be limited in scope, The Wall Street Journal reported. Israel is likely to warn its Arab allies before it retaliates and could limit its attacks to Iran-linked facilities in Syria, according to regional Arab officials.

Already, Iran’s IRGC has enacted emergency measures for its facilities across Syria. Some IRGC members have evacuated their bases in Syria and others are doing so at night when Israeli strikes are most likely. Only a few soldiers are staying behind to defend arsenals.

Iran-linked facilities in Syria are viewed by military experts as an option that would allow Israel to respond but avoid a spiral of tit-for-tat exchanges that lead to a broader conflagration.

ehran, at the same time, has said it would respond to any Israeli action, signaling that it no longer wants to continue its decadeslong shadow war with Israel—fought largely with its proxies—and will now engage directly.

“The smallest action against Iran’s interests will definitely be met with a severe, extensive and painful response against all its perpetrators,” Iranian President Ebrahim Raisi said.

srael already engages in almost daily exchanges of fire with Iran’s most potent proxy, the Lebanese militia Hezbollah. The Israeli military said Tuesday that it had launched airstrikes and killed two senior Hezbollah commanders and a lower-ranking operative who were involved in launching rocket and antitank missile attacks toward Israeli territory. Hezbollah confirmed all three deaths.

The recent exchanges with Hezbollah on Israel’s northern border are considered within the rules of engagement that the two sides unofficially set out at the start of the Gaza war, when Hezbollah began firing on Israeli territory but refrained from sparking a bigger war.

Hezbollah was on higher alert during the Iranian attack over the weekend, anticipating a simultaneous Israeli retaliation that could target Hezbollah positions, according to a person familiar with Hezbollah’s operations. But the group has now lowered its threat level, as Hezbollah estimates Israel won’t hit it in Lebanon in response to Iran’s attack, the person said.

Instead, Hezbollah has received Iranian advice to take precautionary measures in Syria, as Israel could target IRGC bases, warehouses and Hezbollah posts there, the person added.

Syrian security officials said Wednesday that Hezbollah has increased the number of its fighters on the Syrian border with Israel in recent days to collect intelligence on possible Israeli attacks on its fighters and facilities.

Iran also moved to protect its nuclear program over the weekend. United Nations atomic agency chief Rafael Grossi told reporters on Monday that Iranian facilities were closed on the weekend. They reopened Monday. While Iran has restricted the International Atomic Energy Agency’s monitoring of locations related to Iran’s nuclear program in recent years, inspectors now have regular access to the country’s main enrichment facilities.

People familiar with Iran’s nuclear program say Iran keeps its near-weapons-grade 60% fissile material in easily transportable canisters, allowing it to be moved if needed. However, that would likely be detected by the IAEA’s personnel or cameras, and potentially set off a crisis. Iran has pledged to be transparent about its nuclear program.

European Union foreign ministers discussed new sanctions against Iran in a video call on Tuesday. The bloc’s foreign policy chief, Josep Borrell, said Brussels would start working on new measures. It could take a few weeks to approve them, diplomats said.

These will include sanctions on Iran for its delivery of missiles and drones to pro-Iran militias in the Middle East, a measure that had been pushed by France and Germany before Iran’s weekend attack. They will also prepare the ground to sanction Iranian people and entities if it’s proven that Tehran has sent missiles to Russia for its war against Ukraine.

Some EU member states are also pushing again to place Iran’s Revolutionary Guard Corps on the bloc’s terrorist list, as the U.S. has done, a measure that has previously been sidelined by legal and diplomatic hurdles. The EU does already sanction the IRGC for its weapons of mass destruction work.

The Israeli military also continued to operate against Hamas in Gaza in recent days, saying it launched strikes against 40 targets throughout the Palestinian enclave.

Activity in Gaza has slowed in recent weeks, compared with the start of the war, as Israel has weighed whether to mount a decisive operation in the southern city of Rafah—where more than a million Palestinians are seeking refuge—and Israeli officials in recent days have focused on Iran.

But this time they got much more than they wanted. Dubai faced torrential downpours on Tuesday, with flooding shutting down much of the city, including schools and its major airport—killing at least one man whose car was swept away as well as at least 18 others in neighboring Oman, including a bus full of schoolchildren.

The UAE government media office said it was the heaviest rainfall recorded in 75 years and called it “an exceptional event.” More than a typical year’s worth of water was dumped on the country in a single day.