KYIV, Ukraine 

Some 20,800 Russian soldiers have so far been killed in Ukraine, the Ukrainian military claimed on Tuesday.

Ukrainian forces have destroyed 169 Russian aircraft, 150 helicopters, 134 unmanned aerial vehicles (UAVs), 802 tanks, 2,063 armored vehicles, and 386 artillery systems, according to the Ukrainian General Staff’s latest update.

A total of 132 Russian multiple rocket launcher systems, 1,495 vehicles, 76 fuel tanks, 67 anti-aircraft systems, and eight boats have also been destroyed, it added.

Separately, Ukraine’s deputy prime minister said no agreement has been reached with Russia on humanitarian corridors for the evacuation of civilians.

Iryna Vereshchuk said on Telegram that due to violations of agreements by Russian forces, a convoy of humanitarian cargo could not move further beyond the southeastern port city of Berdyansk, southwest of Mariupol.

She said they continue negotiations on the opening of humanitarian corridors in the Kherson and Kharkiv regions.  

Stepped-up Russian attacks

While Russian attacks on the Donbas region have increased in the last two days, there is no agreement on humanitarian corridors between Ukraine and Russia.

Ukrainian authorities on Tuesday said Russian forces have intensified their attacks in the besieged southeastern port city of Mariupol and the eastern Donbas region.

The Ukrainian General Staff said Russian troops are focused on breaking through the defense of Ukrainian troops in the Luhansk and Donetsk regions and establishing full control over Mariupol.

Mariupol officials said the Azovstal metallurgical plant facilities in the city, most of which are currently controlled by Russian forces, were under bombardment throughout the day.

Nearly 1,000 civilians reportedly took refuge in the facilities along with Ukrainian soldiers.

Meanwhile, Luhansk Governor Serhiy Haidai said attacks by Russian troops were repelled by Ukrainian soldiers in the eastern cities of Rubizhne and Popasna.

Haidai called on civilians in Luhansk to urgently move to safe zones in the country.

Kharkiv Governor Oleh Synyehubov said on Telegram that Russian forces continued their missile attacks and artillery strikes on the northeastern Ukrainian city.

Five civilians died, while 17 others were injured in the attacks over the last 24 hours, Synyehubov added.  

Support from Bulgaria

Separately, Ukrainian Foreign Minister Dmytro Kuleba met with his Bulgarian counterpart Teodora Genchovska as part of a two-day official visit to the capital Sofia.

Speaking at a joint press conference with Genchovska, Kuleba thanked Bulgaria for supporting Ukraine's EU and NATO membership bids and hosting Ukrainian refugees.

"We are fighting not only for Ukraine, but for the security of Bulgaria and all the countries of the Black Sea region," Kuleba told reporters.

“We are fighting so that you do not come face to face with Russia's aggression. Today's Russia, which massacres, destroys, tortures and rapes, does not deserve understanding. I want you to understand this.”

She called on all EU and NATO countries to support Ukraine, saying that although Bulgaria is a small state, it provides great assistance to Ukraine.

"Bulgaria is hosting 91,000 Ukrainian refugees. The Bulgarian Red Cross sent €1.5 million and Bulgaria’s Foreign Ministry has sent €185,000 to Ukraine," Genchovska said.

At least 2,072 civilians have been killed and 2,818 injured in Ukraine so far in the war that started on Feb. 24, according to UN estimates, with the true figure believed to be much higher.

More than 4.9 million Ukrainians have fled to other countries, with over 7 million more internally displaced, said the UN refugee agency.  

* Writing by Gozde Bayar and Zehra Nur Duz in Ankara