Russian Foreign Minister Sergei Lavrov and Ukrainian counterpart Dmytro Kuleba on Thursday began talks in Turkey in the first such high-level contact since Moscow invaded its neighbour, officials from both sides and their hosts said.

The ministers began talks on the sidelines of a diplomatic forum in the southern Turkish resort of Antalya, joined by Turkish Foreign Minister Mevlut Cavusoglu, a Turkish official told AFP in comments confirmed by the Russian and Ukrainian foreign ministries.

Turkey has for weeks pushed to play a mediation role in the conflict. But analysts fear there are only the lowest chances of a breakthrough at the meeting.

Images of the meeting showed the Russian, Turkish and Ukrainian delegations sitting on each side of an 'n' shaped table, with each minister accompanied by just two other officials.

Kuleba said in a video on Wednesday that his expectations were "limited" for the talks and said their success would depend on "what instructions and directives Lavrov is under" from the Kremlin.

The meeting is taking place against the background of Ukrainian and international outrage after an attack on a children's hospital in the besieged Ukrainian city of Mariupol which, according to Kyiv, killed at least three people, including a young girl.

The Turkey talks are one of a number of diplomatic initiatives. 

Israel is seeking to broker a solution through direct talks with President Vladimir Putin and French President Emmanuel Macron is also frequently phoning the Kremlin chief.

"There is today a very slim hope and we need to seize it... without being naive," France's Europe Minister Clement Beaune told France Inter radio. 

"The goal is the same that the fighting stops but we need to put great pressure on Russia," he added.

US warns Russia may use biological weapons in Ukraine

The United States on Wednesday rejected Russian claims that it supports a bioweapons program in Ukraine, saying the allegations were a sign that Moscow could soon use the weapons themselves.

"The Kremlin is intentionally spreading outright lies that the United States and Ukraine are conducting chemical and biological weapons activities in Ukraine," State Department spokesman Ned Price said in a statement.

"Russia is inventing false pretexts in an attempt to justify its own horrific actions in Ukraine."

White House Press Secretary Jen Psaki said the claims were "preposterous" and noted that "we've also seen Chinese officials echo these conspiracy theories."

"Now that Russia has made these false claims... we should all be on the lookout for Russia to possibly use chemical or biological weapons in Ukraine, or to create a false flag operation using them," she said on Twitter.

On March 6, Moscow's foreign ministry tweeted that Russian forces found evidence that Kyiv was erasing traces of the military-biological program in Ukraine, allegedly financed by the United States.

Price said "this Russian disinformation is total nonsense" and added that Russia had "a track record of accusing the West of the very crimes that Russia itself is perpetrating."

The United States said Tuesday however it was working with Ukraine to prevent invading Russian forces from seizing biological research material in the country.

Latest developments

Here are the latest developments in Russia's war in Ukraine:

- 35,000 evacuated -

At least 35,000 civilians were evacuated from besieged Ukrainian cities during a 12-hour ceasefire on Wednesday, President Volodymyr Zelensky says.

They left via three humanitarian corridors, and Zelensky says he hopes more civilians will be able to flee Thursday with three additional routes set to open for the cities of Mariupol, Volnovakha and Izium.

- 1,207 dead in Mariupol siege -

A total of 1,207 civilians have died in a nine-day Russian siege of the port city of Mariupol, its mayor says in a message.

Aid groups have warned of catastrophic conditions, with no water, electricity or heat in the city and repeated attempts to establish safe routes out collapsing under attack.

- Fury as children's hospital hit -

Ukraine accuses Russia of a "war crime" over an attack on a children's hospital in Mariupol, which wounded 17 people, officials said.

The US condemns the attack as "barbaric," while Britain deems it "depraved."

Footage shows injured people streaming from the devastated building past cars on fire and a giant crater in front of the facility.

- Fear of Kyiv siege -

Fears are mounting the capital will be encircled, with AFP seeing Russian troops pressing closer. 

Overnight, the Ukrainian General Staff warns Russian forces are continuing their "offensive operation" to surround the city.

- Chernobyl power cut 'not critical' -

Power is entirely cut to the Chernobyl power plant, site of the world's worst nuclear disaster in 1986.

The UN nuclear watchdog IAEA, warns the plant, now in Russian hands, is no longer transmitting data but says it sees no "critical impact on safety".

- Patriot missiles -

The United States has deployed two new Patriot surface-to-air missile batteries in Poland, in keeping with commitments to defend its NATO allies, a senior Pentagon official says.

- But no fighter jets, says US -

Fearing a wider conflict, the Pentagon definitively rejects a Polish offer to deliver its Russian-made MiG-29 fighter jets to a US base in Germany, to be eventually handed over to Ukraine.

Zelensky pleads, "Look, we're at war! Send us the planes."

- More aid -

US lawmakers are voting on a $14-billion aid package for Ukraine with Canada pledging more military equipment.

The International Monetary Fund meanwhile approves $1.4 billion in emergency financing for Ukraine.

- Britain urges G7 oil ban -

British Foreign Secretary Liz Truss calls on the entire G7 to ban Russia oil imports, saying the world's leading economies should "go further and faster" in punishing Moscow for invading Ukraine.

But Group of Seven members including France, Germany, Italy and Japan are wary of such a move.

- US warns on biological weapons-

Washington rejects Russian claims that it supports a bioweapons program in Ukraine, saying the allegations were a sign that Moscow could soon use the weapons themselves.

- 2.2 million flee -

The UN estimates the total number of refugees fleeing Ukraine has risen to around 2.2 million, with more than half in Poland.

It has called the outflow Europe's fastest-growing refugee crisis since World War II.

- Oil falls, stocks surge -

Oil prices tumble while US and European and Asian stocks surge after days of market turmoil over Russia's invasion of Ukraine.