BEIRUT — Israeli warplanes struck eastern Syria overnight, Syria's state-run news agency said Wednesday, hitting targets that a local monitoring group said included Iranian military and associated militia positions and forces loyal to Syrian President Bashar al-Assad.

Shortly after 1 a.m., the Syrian Arab News Agency reported an Israeli attack on the cities of Deir al-Zour and Bukamal in the country’s east, without mentioning deaths or damage. Bukamal is on the Syria-Iraq border and is a vital route for transporting Iranian arms and fighters into Syria.

The monitoring group Deir al-Zour 24, which has an extensive network in the province of Deir al-Zour, said the raids targeted at least four positions of Iran’s Islamic Revolutionary Guard Corps, designated a terrorist organization by the United States.

Al-Mayadeen, a pro-Assad Lebanese TV channel that has extensive field access in Syria, said that “the Israeli aggression targeted positions that had been emptied before the bombardment.” The channel said that only material damage was sustained — a common line by the Syrian government after Israeli attacks — and showed grainy photos of twisted metal, fallen concrete facades and soldiers digging into the rubble.

The channel also said warehouses in western Deir al-Zour were hit, as well as other positions inside the city and in other locations, including the border crossing. Omar Abu Layla, head of Deir al-Zour 24, said the warehouses are some of the largest that Iranian-backed militias have in Syria.

The bombardment lasted for 35 minutes, according to Al-Mayadeen, and was one of the largest attacks on Syria in years. The Israel Defense Forces said it does not comment on reports in foreign media.

Abu Layla said the attack killed no more than 40 members of local and foreign forces loyal to Assad. In a phone call with The Washington Post, he said ­Iranian-backed militias had brought a shipment of missiles into Syria to be stored at the warehouses in the past three weeks.

“This means the Israelis have been monitoring the movement heavily, and the reason behind the massive attack was to target these missiles,” he said, speaking from Germany, where is he based.

“We have not noted any huge attacks like the one last night in two years,” he said, adding that this is the largest Israeli attack on Iranian positions in Syria in the past decade. The attack largely targeted two cities and the 53-mile stretch of desert between them, controlled by pro-Iranian forces. Abu Layla noted that the fierceness of the attack came at the tail end of President Trump’s administration, a time when Israel might be more emboldened to attack such targets. 

Israeli warplanes have been flying low over Lebanon almost daily for three weeks, occasionally venturing into Syria for an attack. The thundering sound and the buzzing of drones have especially unnerved residents of Lebanon’s capital, Beirut, which suffered an explosion at its port in August that killed 200 people and destroyed much of the city’s center.

Israel has stepped up its attacks on Syria recently. In 2020, it conducted 50 strikes in Syria, according to the IDF’s statistics. Last month, the IDF chief of staff, Lt. Gen. Aviv Kochavi, said, “The Iranian entrenchment in Syria is in a clear slowdown as a result of IDF activity, but we still have a long way to go to complete our goals in this arena.”

The stepped-up Israeli attacks in Syria come as forces in the region are on alert during the last chaotic days of the Trump administration.

Israeli Prime Minister Benjamin Netanyahu had reportedly pressed Trump, who has strongly supported Israel’s campaign, to put pressure on Tehran’s nuclear program, to deliver a final military blow to the program before turning Iran policy over to ­President-elect Joe Biden. That prospect was dampened by reported objections from Pentagon officials.

But the mounting upheaval in Washington, with Trump now impeached for a second time, has heightened the sense of unpredictability. The IDF has been on high alert in recent days and has deployed a battery of its Iron Dome air defense missiles to the Red Sea city of Eilat to protect against possible strikes from ­Iranian-backed forces in Yemen, according to a report in the daily Haaretz newspaper.

Defense analysts believe that Israel may be taking advantage of the uncertainty of Trump’s last days as well as the failure, so far, of Iran to respond to recent provocations. Israel is widely believed to have been behind the killing of a top Iranian nuclear scientist in November. And Jan. 3 was the first anniversary of the U.S. drone strike in Baghdad that killed Iranian Maj. Gen. Qasem Soleimani, commander of the Revolutionary Guard’s elite expeditionary Quds Force. So far, none of Iran’s promised revenge attacks have materialized.

“Israel seems to have been exploiting Iran’s comparative weakness in Syria and the waiting game Tehran is playing prior to U.S. President Joe Biden’s inauguration,” defense analyst Amos Harel said in a Haaretz commentary.

Steve Hendrix in Jerusalem, Shira Rubin in Tel Aviv and Nader Durgham in Beirut contributed to this report.