US president Donald Trump engaged in high-level diplomacy on his 80th birthday, today speaking to Ukrainian president Volodymyr Zelensky and Russian leader Vladimir Putin.

Zelensky discussed the ongoing invasion of his nation with Trump on Sunday. 

The world leaders spoke about the war, diplomacy and peace negotiations over the phone. 

Zelensky also wished Trump a happy birthday during the call that lasted around half an hour. 

Putin also spoke to the US president, discussing the invasion of Ukraine as well as an upcoming visit of Washington's envoys to Russia, the Kremlin said.

'The conversation focused on the situation surrounding the memorandum of understanding being drafted between the United States and Iran. Donald Trump said an agreement is close,' Kremlin aide Yuri Ushakov told reporters.

Ushakov also said that 'it has been agreed that US presidential special representatives Steve Witkoff and Jared Kushner, who are currently closely involved in Iranian affairs, will return to Russia soon'.

It comes as a Ukrainian drone attack killed one person in Russia's southwestern Oryol region, local officials said today, while a separate strike hit an oil facility as part of Kyiv's campaign of strikes on military and energy targets deep inside Russia.

Oryol regional governor Andrei Klychkov said today that one person died and nine were wounded when a Ukrainian drone struck a residential building overnight in the regional capital, also called Oryol.

Local authorities in Russia's Yaroslavl region, around 440 miles from the Ukrainian border, said fuel storage facilities caught fire after being hit by a drone.

Zelensky said his country's forces had 'struck an oil facility that was important for the reserve of the aggressor state' in the Yaroslavl region.

Ukraine has stepped up its attacks on Russia's oil and gas facilities in recent months, arguing the energy sector funds and directly fuels Moscow's more than four-year invasion.

Meanwhile, Britain is investigating a sanctioned tanker that is suspected of being part of the Russian 'shadow fleet,' shipping oil in violation of international sanctions over Moscow's war on Ukraine, British Prime Minister Keir Starmer said Sunday.

British armed forces boarded and detained the vessel, the Smyrtos, on Sunday in the English Channel, in what the MoD called 'the first UK-led operation of its kind.'

Russia is believed to be using a fleet of hundreds of ships to evade sanctions over its war against Ukraine.

'This operation delivers yet another blow to Russia and reminds those fuelling Putin's war in Ukraine that they cannot hide,' Starmer said.