TEHRAN : The United States military launched "powerful" strikes on Iran on Thursday, in retaliation for Tehran's attacks targeting US bases in Jordan as the Middle East war reignited and again drew in the Islamic republic's proxies.

The first strikes after a nearly week-long lull in fighting dashed hopes of a return to negotiations.

"The strikes are a powerful response to yesterday's attempted Iranian attacks on US forces based in the Middle East", US Central Command said.

Saudi Arabia and the United States also announced strikes Wednesday on militant bases in Iraq, while US ally Israel accused Iran-backed Hezbollah of a truce violation.

For two days, the world's biggest oil exporter Saudi Arabia has reported drone attacks targeting crude facilities that it blamed on Iraqi armed groups allied with Tehran.

Iran meanwhile launched missiles at US ally Jordan, with Iranian state media later reporting an American attack near the Islamic republic's border with Iraq.

Ahead of the latest strikes, US President Trump told Fox News: "We'll be hitting them hard...We are going to beat the 'effing s' out of them."

- 'Resistance' -

Iran's state television, meanwhile, reported a US strike in the Piranshahr border area, after the Fars news agency reported a missile hit an uninhabited area, causing no casualties.

Earlier, Jordan's army said it had intercepted five Iranian missiles, with Iran's Revolutionary Guards saying they had targeted US bases there.

"As long as the threats against the Islamic Republic of Iran continue...the resistance will continue," they added.

On another front, Israel accused Hezbollah of deploying a drone overnight against an Israeli vehicle inside Lebanon, in what the military called "a blatant violation of the ceasefire".

Israel fought alongside the US in the first weeks of the war against Iran, while battling Hezbollah in Lebanon, but it has yet to join the latest round of strikes against the Islamic republic.

- 'Dangerous' -

US stocks ended sharply lower on the oil price jump Wednesday, while the yield on 30-year US Treasury bonds hit their highest levels since 2007.

In Iraq, a joint US-Saudi air operation followed attacks by what Riyadh called "terrorist militias loyal to Iran" on its oil facilities.

The US military said logistics and weapons sites belonging to an Iran-aligned group were targeted in the strikes.

Iraq's Hashed al-Shaabi alliance said the attacks killed at least 20 of its members.

It denounced a "dangerous escalation" against an "official security institution".

Two Hashed officials said five Iranian advisors were among those killed, and AFP correspondents saw coffins draped with Iranian flags.

The Hashed al-Shaabi alliance, also known as the Popular Mobilisation Forces, was created in 2014 to fight jihadists before its integration into the military.

It includes brigades belonging to Iran-backed groups reputed for acting unilaterally.

Iraq denounced the US-Saudi strikes and said it rejects "all acts of aggression, regardless of the party responsible or the justifications presented".

The Ministerial Council for National Security said it would "confront any violation of Iraq's sovereignty, and prevent any source from using Iraqi territory to threaten neighbouring states".

According to Fox News, however, Trump said the strikes were "coordinated with the Iraqi government".

The strikes follow growing US pressure on Iraq to disarm pro-Iran groups. Earlier this month, Prime Minister Ali al-Zaidi visited both the US and Iran.

- Red Sea -

The US had said the days-long cessation in fighting was aimed at kickstarting a new round of negotiations, including over the Strait of Hormuz, which Iran has blockaded throughout much of the war.

The Revolutionary Guards said they had attacked and stopped three tankers in the strait, insisting Iran has "full control" of the waterway that was previously free to transit.

Tehran has insisted it will retain control of the crucial conduit for energy shipments, and has also announced plans to collect fees for passage, which Washington opposes.

The US also announced new sanctions targeting entities linked to Iran's Guards that it accused of extorting ships transiting the strait.

The Hormuz closure has lent greater significance to the Red Sea, Riyadh's alternative export route.