The Russian military alleged Thursday that its forces have managed to capture more of the outer neighbourhoods of Mariupol, in southeastern Ukraine, saying the operation to "liberate" the strategic port city is ongoing.

The claim came a day after a Russian airstrike destroyed a children’s hospital and maternity ward in Mariupol, where heavy fighting has been taking place in recent days.

Local authorities in the besieged city have accused Russian forces of waging a "medieval siege" against them.

-ABC News' Patrick Reevell

The top diplomats from Russia and Ukraine are meeting now in Antalya, Turkey.

Russian Foreign Minister Sergey Lavrov and Ukrainian Foreign Minister Dmytro Kuleba arrived in the southern Turkish resort on Thursday morning ahead of the meeting -- the highest level talks between their two countries since Russia invaded Ukraine on Feb. 24.

Both officials first met separately with their Turkish counterpart, Mevlut Cavusoglu, upon arrival. Cavusoglu is expected to attend their talks.

Lavrov and Kuleba are expected to talk for about 90 minutes. They will hold separate press conferences afterwards.

-ABC News' Engin Bas and Joe Simonetti

Russia’s foreign ministry has claimed that Ukraine put firing positions inside the children’s hospital and maternity ward in Mariupol, Ukraine, that was destroyed by shelling Wednesday.

There is currently no evidence to support the claim, made by Foreign Ministry spokeswoman Maria Zakharova during a daily briefing Wednesday. The comment appears to be an implicit acknowledgment that Russia deliberately targeted the hospital, as Ukrainian officials had claimed.

Independent investigations found that in Syria, Russia’s air force deliberately bombed hospitals in rebel-held areas as a tactic of war.

-ABC News' Patrick Reevell

The State Department spoke out against the Kremlin's allegations of U.S. chemical or biological weapons activity in Ukraine.

"Russia has a track record of accusing the West of the very crimes that Russia itself is perpetrating," State Department spokesperson Ned Price said in a statement Wednesday, calling the allegations of U.S. biological weapons labs and chemical weapons development in Ukraine "outright lies," "conspiracy theories," "disinformation" and "total nonsense."

"Russia is inventing false pretexts in an attempt to justify its own horrific actions in Ukraine," he continued. "The United States does not own or operate any chemical or biological laboratories in Ukraine, it is in full compliance with its obligations under the Chemical Weapons Convention and Biological Weapons Convention, and it does not develop or possess such weapons anywhere."

-ABC News' Conor Finnegan

Russian President Vladimir Putin claimed there have been “certain positive movements” in negotiations with Ukraine, “which are emerging almost daily."

Putin made the remarks in a televised meeting in the Kremlin with Belarus’ leader Alexander Lukashenko.

A third round of talks last week ended without any resolution, although the sides agreed to open humanitarian corridors to allow the evacuation of civilians.

But this week Russia has seemed to make subtle shifts in its demands, which suggest it might be slightly moderating its position in the face of heavy casualties in Ukraine and an unexpectedly intense global backlash.

The Kremlin ahead of the last round of talks announced its conditions for ending the war, saying Ukraine must change its constitution to guarantee it will never join political blocs, interpreted as meaning NATO or the European Union, and it must also recognize Crimea as part of Russia and the independence of the two Russian-controlled separatist regions in eastern Ukraine.

The demands are still maximalist but there was no reference to removing Ukraine’s current government under president Volodymyr Zelenskyy, suggesting the Kremlin may have quietly dropped the goal.

-ABC News' Patrick Reevell