Russia is blocking humanitarian access to the besieged port city of Mariupol because it wants to hide evidence of "thousands" of people killed there, Ukrainian President Volodymyr Zelensky said on Wednesday.

"The reason why we cannot get into Mariupol with the humanitarian cargo is precisely because they are afraid... that the world will see what is going on there," Zelensky told Turkey's Haberturk TV.

"I think it's a tragedy there, it's hell, I know that it's not tens, but thousands of people, different people, who have been killed there and thousands wounded," Zelensky said.

However, he expressed confidence that Russia would not succeed in concealing all the evidence. 

"They will not be able to hide all of this and bury all of these Ukrainians who died and who are injured. It's just such a number, it's thousands of people, it's impossible to hide."

Zelensky said that Russia had already attempted to conceal evidence of crimes in the town of Bucha outside of Kyiv and several nearby communities, where Ukrainian officials have accused Moscow of carrying out widespread killings of civilians.

"They burned families. Families. Yesterday we found again a new family: father, mother, two children. Little, little children, two. One was a little hand, you know," Zelensky said. "That's why I said 'they are Nazis'."

Asked about continuing peace talks with Russia, Zelensky said "they will have to take place anyway".

"I think it is difficult to stop this war without it," Zelensky said.

But he added that he had a tough time bringing himself to continue talks with Moscow "because we understand who we are dealing with".

'Small number' of Ukraine soldiers get drone training in US

Ukrainian soldiers are being trained in the United States to operate the deadly Switchblade drones that Washington is supplying to Kyiv, a Pentagon official said Wednesday. 

Defense Department spokesman John Kirby said it was a "very small" number of Ukrainian troops who were already present in the US before Russia invaded their country.

"We took the opportunity, having them still in the country, to give them a couple of days' worth of training on the Switchblades, so they can go back... to train others in the Ukrainian military," according to Kirby.

He said the 100 drones, which are essentially remotely controlled flying bombs which are crashed into targets where they explode, have been sent to Ukraine to bolster the military's fight against Russian troops.

"They arrived over there earlier this week. So they'll be getting into Ukraine quickly if they aren't already there," Kirby said, adding that the number of Ukrainian trainees was less than a dozen.

President Joe Biden announced on March 16 that, among other weaponry and munitions Washington was shipping to the Ukrainians, it would start sending the Switchblades.

Named for the way their wings unfold when launched, Switchblades are called loitering munitions, because they can be flown to target areas and held there until the right moment when a target is identified.

The operator then flies them into the target where they explode.

The original version, small enough to carry in a backpack, was used by US forces in Afghanistan.

A larger version, with enough explosives to take out armored vehicles, has also been developed. But the Pentagon would not say which one has been sent to Ukraine, if not both.

Meanwhile the United States announced Tuesday it was releasing another $100 million worth of military aid to Ukraine as its forces push Russians out from the Kyiv region.

Six weeks after Russia invaded and tried to quickly capture the capital, Kirby said they failed and had "completely withdrawn" from the Kyiv area as well as Chernigiv to the north.

Moscow has indicated it is preparing to intensify fighting in eastern and southern Ukraine, where its forces hold major chunks of territory.

But Kirby said the Pentagon had not yet seen a significant influx of reinforcement troops into that region, particularly the pro-Moscow Donbas area.

Latest developments

Here are the latest developments in the war in Ukraine:

- Leave 'now', residents in east Ukraine told -
Ukraine tells residents in the country's east to evacuate "now" or "risk death" ahead of a feared Russian onslaught on the Donbas region, which Moscow has declared its top prize.

Deputy prime minister Iryna Vereshchuk writes on Telegram that the governors of the Lugansk and Donetsk regions, part of the Donbas, and the nearby city of Kharkiv "are doing everything to ensure that the evacuations take place in an organised manner."

- Bucha killings 'war crimes': Biden - 
US President Joe Biden has denounced the killing of Ukrainian civilians in the town of Bucha allegedly by Russian troops as "war crimes."

"Civilians executed in cold blood, bodies dumped into mass graves, the sense of brutality and inhumanity left for all the world to see, unapologetically. There's nothing less happening than major war crimes," he said, urging the world to hold the killers accountable.

- Putin speaks on Bucha -
Russian President Vladimir Putin accuses Ukrainian authorities of being behind "crude and cynical provocations", after they said hundreds of civilians were found dead in the town of Bucha when Russian troops withdrew.

- Denials 'not tenable' -
The Berlin government says that satellite images from last month provided strong rebuttal of Russian denials of involvement in civilian deaths in Bucha.

"Russian declarations" that images of civilian deaths "were posed scenes or that they were not responsible for the murders are in our view not tenable", government spokesman Steffen Hebestreit says.

- Putin daughters sanctioned -
The United States announces sanctions on two daughters of Putin, saying family members are known to hide the Russian president's wealth.

It also declared "full blocking" sanctions on Russia's largest public and private financial institutions, Sberbank and Alfa Bank, and says all new US investments in Russia are now prohibited.

The EU is also looking to add Putin's daughters to its sanctions blacklist, European diplomats tell AFP.

- More UK sanctions -
Britain has slapped new sanctions on Russia, targeting two banks and eliminating all Russian oil and coal imports by the end of the year.

The latest UK measures also outlaw all new British investment into Russia.

- Four said killed in Donetsk -
Russian strikes have killed four people and wounded four others near a humanitarian distribution point in the east Ukraine region of Donetsk, the regional governor said.

- 'Long' war ahead -
NATO chief Jens Stoltenberg says there is no sign Putin has dropped "his ambition to control the whole of Ukraine".

- Orban invites Putin, Zelensky -
Hungarian Prime Minister Viktor Orban, one of Putin's rare allies in Europe, says he has urged the Russian leader to declare an immediate ceasefire in Ukraine.

He also invites the leaders of France, Germany and Ukraine to meet Putin in Budapest.

- UN rights body suspension -
The UN General Assembly will vote Thursday on suspending Russia from the UN Human Rights Council as punishment for invading Ukraine, the assembly presidency says.

A day earlier Ukrainian President Volodymyr Zelensky had also called for Russia to be expelled from the UN Security Council "so it cannot block decisions about its own aggression, its own war."

- Dollar debt paid in rubles -
Russia says it had made payments on dollar-denominated foreign debt in rubles, adding to fears the country is headed for a sovereign default.

The finance ministry says it was forced to make the $649.2-million payment in rubles after an intermediary bank refused to execute the payment but did not say whether the payment was accepted.

- 'Not far short of genocide': Johnson -
British Prime Minister Boris Johnson says the alleged massacre in Bucha "doesn't look far short of genocide to me" and that Britain will also step up sanctions on Russia.

US President Joe Biden has branded Putin a war criminal.

- Pope slams 'horrendous cruelties' -
Pope Francis says during his weekly audience the "recent news about the war in Ukraine, instead of bringing relief and hope, instead attests to new atrocities, such as the Bucha massacre."

- Red Cross convoy -
A Red Cross convoy arrives in the southern Ukrainian town of Zaporizhzhia after failing to reach the besieged port city of Mariupol, an AFP journalist reports.

Seven buses with around 300 people onboard accompanied by the International Committee of the Red Cross and at least 40 private cars arrive in the southern town.