The ripple effects of the fighting are also being felt in Ukraine, four years into Russia's invasion. Here's what we know:

- Peace talks -

US President Donald Trump -- seeking a win as a mediator of the war -- has been pushing the two sides to agree a deal to end the bloodiest war in Europe since World War II.

But the fighting with Iran appears to have derailed the latest round of talks aimed at ending Russia's invasion.

President Volodymyr Zelensky said this week that a third round of trilateral negotiations with US and Russian officials had tentatively been scheduled for Thursday and Friday in Abu Dhabi.

But the United Arab Emirates is among the Gulf countries that have been targeted by Iranian strikes.

A source close to the Ukraine negotiators told AFP on Wednesday that there was no concrete date set for the next round of negotiations.

Zelensky said he would also back alternative venues like Turkey or Switzerland -- both of which have hosted previous meetings on the war.

There is also the question of what diplomatic resources Ukraine's allies can spend on halting Russia's invasion while the war against Iran is ongoing.

Several US diplomats engaged in the Ukraine talks also led negotiations with Iran that broke down last month.

"The war in Iran will not lead to the termination of negotiations on ending the war in Ukraine, although for the Americans, Iran will of course be the main priority in the near future," said Volodymyr Fesenko, a Ukrainian political analyst.

However, "the scale and consequences of the war in Ukraine are too great for it to be forgotten," he added in a social media post.

- Iranian drones and air defence -

Zelensky has conceded that a long war in Iran could impact US deliveries of ammunition for air defence systems that were given to Ukraine by Western allies for the defence of critical infrastructure facilities, particularly energy sites.

A close ally of Tehran, Russia has been using Iranian-designed Shahed drones throughout its four-year invasion, the same projectiles Tehran has been deployed across the Gulf.

Kyiv has developed a range of cheap and effective drone interceptors -- aerial craft designed to hit incoming attack drones mid-air -- that it says are world-leading.

Zelensky on Tuesday offered US allies in the Middle East a swap of some of their air defence missiles in exchange for those interceptors, which he said would better protect them from Iranian drone attacks.

"Let's speak about weapons that we're short of: PAC-3 missiles -- if they give them to us, we will give them interceptors," he said.

Analysts say there is little to indicate the Iran war could impact fighting across Ukraine's sprawling front line.

- Oil prices and the Russian war chest -

Ukraine has since the beginning of the war escalated its long-range attacks on Russian oil and gas facilities with the aim of denting energy revenues that fund its invasion of Ukraine.

Western sanctions have also targeted Moscow's ability to export oil and gas.

Energy revenues have recently fallen to a five-year low and the economy is under increasing strain.

But the war in Iran -- including drone attacks on Gulf energy sites -- has spooked markets and significantly pushed up oil prices, meaning Moscow could secure bigger revenues to fund its war chest.

"The longer the crisis in the Persian Gulf lasts, the more beneficial it will be for Russia, and the more funds its budget will receive to finance its aggression against Ukraine," said Vyacheslav Likhachev, a member of the Expert Council of the Center for Civil Liberties, a Ukrainian non-profit.