Western officials are voicing mounting concern over the risk of a regional “spillover” from the conflict between Israel and Hamas, as US forces in the region come under repeated drone attack, including in Iraq. Amid indications that Israel may be poised to launch a major ground offensive into Gaza, and escalating tensions on Israel’s boundary with Lebanon, Iranian proxies in particular appeared to be stepping up their threats. The Ain al-Asad airbase, which hosts US and other international forces in western Iraq, was targeted by drones and missiles on Thursday evening, according to security sources. Multiple blasts were reportedly heard inside the base. The Iraqi military said it had closed the area around the base and started a search operation. It was not clear yet whether the attacks had caused casualties or damages. The assault came after rockets hit another military base hosting US forces near Baghdad’s international airport on Thursday, according to Iraqi police. US military forces in Iraq were also targeted on Wednesday in two separate drone attacks, with one causing minor injuries to a small number of troops even though the US military managed to intercept the armed drone. On Wednesday, a drone hit US forces in Syria, resulting in minor injuries, while another one was brought down. Earlier on Thursday, the USS Carney, a navy destroyer in the northern Red Sea, intercepted three land attack cruise missiles and several drones that were launched by Houthi forces in Yemen. A Pentagon spokesperson told reporters the missiles were “potentially” headed toward Israel but said the US had not finished its assessment of what they were targeting. The action by the Carney potentially represented the first shots by the US military in the defence of Israel in this conflict. The events of the past fortnight, since Hamas massacred more than 1,400 Israelis in a surprise attack on communities near the Gaza border and took almost 200 hostages, have posed serious political dilemmas for states with peace treaties with Israel – Jordan and Egypt – and those that have been edging towards normalising relations, including a number of Gulf states. The ferocity of Israel’s airstrikes on Gaza after Hamas’s murderous assault, and the accompanying rhetoric, has provoked demonstrations across the region, pushing governments from Cairo to Riyadh to walk a tightrope of political statements not always backed by the same sentiments in private. That has been exploited by Tehran and its proxies in Iraq, Lebanon, Syria and Yemen, who have taken an increasingly hostile posture, including towards US forces in the region, as the prospect of an Israeli ground offensive edges ever closer. Last week it was reported that Iran had warned Israel via the UN that it would have to “intervene” if Israel invaded Gaza. That message was amplified on Thursday by a deputy commander of Iran’s Islamic Revolutionary Guard Corps, Gholamhossein Gheybparvar, who in a speech said that Iran-backed militia in Iraq, Lebanon, Syria and Yemen were ready to strike Israel if its ground forces invaded Gaza. The posture of Iran and its proxies, not least Hezbollah in Lebanon, which poses the most direct threat to Israel from the north, continues to be ambiguous, with Hezbollah allowing Palestinian factions in Lebanon to fire missiles. On Friday Hezbollah issued a statement saying it had targeted Israeli positions in the contested Shaba farms with guided missiles and other “appropriate” weapons. Earlier, unidentified gunmen were reported to have infiltrated the northern Israeli community of Margaliot, to which Israel retaliated with artillery fire. More widely, Tehran appears to have reactivated a strategy – launched in 2019 before the US assassination of the head of the Iranian al-Quds force, Qassem Soleimani, in a missile strike in Baghdad – to target US forces. While the death of Soleimani, the architect of Tehran’s modern iteration of the so-called “axis of resistance”, plunged that network of proxies into disarray, events of the past week suggest it has reconfigured, with attack drones so far its preferred weapon. Iran historically has been highly averse to direct involvement in conflict, after its experiences of the Iran-Iraq war from 1980 to 1988 in which it lost at least 500,000 fighters, but in recent years it has pursued a much more aggressive regional policy via its proxies, increasing the risk of a catastrophic misjudgment. Amid concerns over the potential for an intervention by Tehran and its allies, Joe Biden has sent two aircraft carriers, other warships and about 2,000 marines to the region. US officials have said Washington is on heightened alert for activity by Iran-backed groups. This week the US also encouraged American citizens in Lebanon to leave by any available flight amid fears the violence could spill over, perhaps seeing the opening of a second front between Hezbollah and Israel. One concern, increasingly being voiced by US officials, is that a deliberate effort could be made to draw Washington into the conflict via militias attacking US forces in Iraq and Syria. Briefing journalists on Thursday, the Pentagon spokesperson, Gen Patrick Ryder, said: “Right now, this conflict is contained between Israel and Hamas, and we’re going to do everything we can to ensure deterrence in the region, so that this does not become a broader regional conflict.” Israel has called up a record 360,000 reservists and has been bombarding the Gaza Strip after Hamas’s 7 October assault. At least 3,785 Palestinians have been killed and 12,493 wounded in Israeli strikes on Gaza, according to the Hamas-run health ministry in the territory. On Thursday, the European Commission president, Ursula von der Leyen, said the risk of regional spillover from the Israel-Hamas war was “real”. Speaking at the Hudson Institute in Washington, Von der Leyen also said dialogue between Israel and its neighbours must continue. “We have seen the Arab streets fill with rage all across the region. So the risk of a regional spillover is real,” she said. “Iran, Hamas’s patron, only wants to fuel the fire of chaos,” she added. Underlining the risk, Belgium on Friday became the latest country to advise its citizens to leave Lebanon, seen as one of the most likely countries to be sucked in. In Lebanon’s southern city of Tyre, the head of the municipal council said in a statement that 7,500 families had abandoned their houses in the southern border region and sought shelter in different municipalities of the city.