Ukraine war latest: US and Russia 'closing on nuclear treaty deal'

We're pausing our live coverage.

Before we go, here's a summary of today's main stories surrounding the war in Ukraine:

• Ukraine and Russia concluded a second day of US-brokered peace talks in Abu Dhabi.
• The discussions have seen the first prisoner exchange deal between the two sides in five months, with 157 people released by each country.
• Reports suggest the US and Russia are close to agreeing an extension to the START nuclear treaty, which expired today.
• Ukraine's military said it had carried out a series of "successful" strikes in January on a launch site for Russian intermediate-range ballistic missiles.
• Ukraine's energy minister warned blackouts across the country could worsen in the coming ‌days, as Moscow's attacks continue to cripple its energy infrastructure.

Russia's foreign ministry said today it had expelled a German diplomat in response to what it insisted was Berlin's unfounded expulsion of a Russian diplomat accused of espionage in January.

The ministry claimed in a statement that Germany's accusations that the Russian diplomat had been engaged in spying were fabricated and a provocation.

"The expulsion of a German diplomat from Russia is completely unfounded and totally unacceptable," said German foreign minister Johann Wadephul, adding that Russia was resorting to unjustified retaliatory measures instead of diplomacy.

Speaking during a trip to Brunei, Wadephul said the diplomat in question was a member of the military attache staff at the German Embassy in Moscow.

"We reserve the right to take further action," he added.

Security services across Europe have warned of a growing threat from Russian intelligence agencies seeking to deter Western powers from supporting Ukraine.

We return now to the story around the 157 Ukrainian prisoners exchanged in return for the same number of Russian captives being freed.

Video posted by Volodomyr Zelenskyy shows a number of the Ukrainians as they arrived by coach back in territory held by Kyiv.

Captioned simply "home", a number of the freed prisoners are seen embracing and making emotional phone calls to loved ones.

Following a day in which there has been significant focus on the expiration of the START nuclear treaty, a new report indicates what would be a major development in the story.

According to three sources cited by Axios, the US and Russia are "closing in on a deal" to continue the treaty.

Two of the sources said a draft plan provisionally agreed by officials from each country still had to be approved by Donald Trump and Vladimir Putin.

Axios adds that it understands the two sides have agreed to extend the existing deal by six months while the negotiations are finalised.

We'll bring you more details on this story as we get it.

In the meantime, you can read more about the significance of the treaty's expiration here:

A little more now on the expiration of the START nuclear treaty, which Moscow previously offered to extend for a year on the same terms.

The US has yet to respond to the offer, but Kremlin spokesman Dmitry Peskov said Moscow would be receptive to proposals from Washington.

"If there are any constructive responses, of course we will engage in dialogue," Peskov said.

As well as images of Ukrainian prisoners being freed today, we can also bring you pictures of what is said to be Russian soldiers being released.

In these still images from a video released by Moscow's defence ministry, soldiers draped in Russian flags boarding a busy at an unknown location in Belarus.

Ukraine is ready to swap its drones for air defence missiles and Polish fighter jets, Volodymyr Zelenskyy said today at a news conference in Kyiv with Polish Prime Minister Donald Tusk.

Zelenskyy also said the pair discussed the development of power grid connectivity between Poland and Ukraine, whose energy system has been badly impacted by Russian air strikes in recent months.

Tusk, meanwhile, said Poland was preparing a new 200 million zloty (£41m) aid package for Ukraine mainly made up of armoured equipment.

He said Poland could give Ukraine MiG-29 fighter jets at any time, but that Zelenskyy had told him Kyiv may need other air-defence equipment as a higher priority, and that he would discuss this with Polish officials and get back to the Ukrainian leader about it on Monday. 

Volodomyr Zelenskyy has been speaking about the prisoner swap we reported earlier, in which 157 prisoners each were released by Ukraine and Russia.

The Ukrainian president said most of those freed by Russia had been in captivity since 2022.

"Today's exchange took place after a long pause, and it's very important that it was able to be implemented," he said.

"Thank you to everyone who works for the exchanges, and to everyone who on the frontline replenishes the exchange fund for Ukraine.

"Without the determination of our soldiers, such exchanges would be impossible, so every result of our units is what sustains the ability to bring Ukrainians home from Russia.

"We will continue our work to free our people from captivity. We must return and we will definitely return everyone. We are working on every single name. So that every family can wait for their loved ones."

Ukrainian officials said more more than half of those released were captured during the defence of Mariupol.

They said 139 of the 157 had been in Russian captivity since 2022.  

The youngest person freed was 23 years old, having been captured at the age of 19. The oldest was 63.

Ukraine and Russia have now concluded a second day of US-brokered peace talks in Abu Dhabi.

As reported, the discussions have seen the first prisoner exchange deal between the two sides in five months.

US envoy Steve Witkoff called the talks "detailed and productive" in an online post but said "significant work remains".

Despite pressure by the Trump administration on both Kyiv and Moscow to find a compromise, however, the two sides have so far failed to agree on a ceasefire.

The fate of the eastern Donetsk region is one of the most complicated issues in the talks.

As a precondition for any deal, Moscow wants Kyiv to pull its troops from all of the Donetsk region, including a line of heavily fortified cities regarded as one of Ukraine's strongest defences.

Ukraine has insisted the conflict should be frozen along the current front lines and rejects any unilateral pullback of its forces.

Kyiv says it wants control of the Zaporizhzhia nuclear power plant, the largest in Europe, which is in Russian-controlled territory. Russia said today it was ready for international cooperation over the Zaporizhzhia plant, including with the US, but that the facility must be Russian.

Russia occupies about 20% of Ukraine's national territory, including Crimea and parts of the eastern Donbas region seized before the 2022 invasion. Analysts say Russia has gained about 1.5% of Ukrainian territory since early 2024. 

Sweden's government announced today that it will provide aid  to Ukraine's energy system worth 1bn Swedish crowns (£81.64m).

Sweden joined NATO in 2024, having historically avoided military alliances for more than 200 years.