US President Donald Trump is considering sending Tomahawk long-range cruise missiles to Ukraine, saying it would provide "a new step of aggression" in its war with Russia.

When asked on Air Force One if he would send Tomahawks to Ukraine, Trump replied, "we'll see... I may".

It follows a second phone call at the weekend between Trump and Ukrainian President Volodymyr Zelensky, who pushed for stronger military capabilities to launch counter-attacks against Russia.

Moscow has previously warned Washington against providing long-range missiles to Kyiv, saying it would cause a major escalation in the conflict and strain US-Russian relations.

Tomahawk missiles have a range of 2,500 km (1,500 miles), which would put Moscow within reach for Ukraine.

Trump spoke to reporters as he flew to Israel. He said he would possibly speak to Russia about the Tomahawks requested by Ukraine.

"I might tell them [Russia] that if the war is not settled, that we may very well, we may not, but we may do it."

"Do they [Russia] want Tomahawks going in their direction? I don't think so," the president said.

Kyiv has made multiple requests for long-range missiles, as it weighs up striking Russian cities far from the front lines of the grinding conflict.

In their phone calls Zelensky and Trump discussed Ukraine's bid to strengthen its military capabilities, including boosting its air defences and long-range arms.

Ukrainian cities including Kyiv have come under repeated heavy Russian bombardment with drones and missiles. Russia has particularly targeted Ukraine's energy infrastructure, causing power cuts.

Last month, Trump's special envoy to Ukraine Keith Kellogg suggested the US president had authorised strikes deep into Russian territory, telling Fox News "there are no such things as sanctuaries" from attacks in the Russia-Ukraine war.

Russia, which launched its full-scale invasion of Ukraine in February 2022, downplayed the chances of Tomahawks changing the course of the war.

Kremlin spokesperson Dmitry Peskov said last month: "Whether it's Tomahawks or other missiles, they won't be able to change the dynamic."