Emergency service workers extinguish fire after a missile strike, as Russia's invasion of Ukraine continues, in Odesa Oblast, Ukraine April 23, 2022, in this picture obtained from social media.  State Emergency Service Of Ukraine in Odesa Oblast/Handout v
Emergency service workers extinguish fire after a missile strike, as Russia's invasion of Ukraine continues, in Odesa Oblast, Ukraine April 23, 2022, in this picture obtained from social media. State Emergency Service Of Ukraine in Odesa Oblast/Handout via REUTERS . Reuters / STATE EMERGENCY SERVICE OF UKRAI

U.S. Secretary of State Antony Blinken and Defence Secretary Lloyd Austin arrived in Kyiv late on Sunday and held talks President Volodymyr Zelenskiy, an aide to the Ukrainian leader said, as Russia's invasion entered a third month.

Zelenskiy is expected to have asked them for more powerful weapons to repel a Russian offensive in the south and east, which he has dubbed the Battle of the Donbas.

The trip by Blinken and Austin, announced earlier by Zelenskiy, would be the highest-level visit to Ukraine by U.S. officials since Russian President Vladimir Putin ordered the invasion of the country on Feb. 24.

Washington has not confirmed that Blinken and Austin were in the Ukrainian capital, as it typically withholds information on sensitive visits in conflict zones for security reasons.

Late on Sunday, Oleksiy Arestovych, an adviser to Zelenskiy, said in a social media video that Blinken and Austin had arrived in Kyiv and were holding talks with the Ukrainian president.

"We are inspired by the resilience of Orthodox Christians in Ukraine in the face of President Putin's brutal war of aggression," Blinken said earlier on Twitter.

Zelenskiy on Twitter thanked U.S. President Joe Biden and the United States for leadership in supporting Ukraine.

Earlier on Sunday, Zelenskiy said his nation would overcome "dark times," in an emotional address at Kyiv's 1,000-year-old Saint Sophia Cathedral to mark Orthodox Easter as fighting in the east overshadowed the religious celebrations.

After Ukrainian fighters forced a Russian retreat from around Kyiv, Moscow's assault is now focused on the eastern Donbas region and the south of the country.

With a semblance of normal life returning to the capital, several countries have reopened embassies in recent days and some residents who fled the fighting returned for Easter.

Moscow, which describes its actions in Ukraine as a "special military operation", denies targeting civilians and rejects what Ukraine says is evidence of atrocities, saying Kyiv staged them to undermine peace talks.

Pope Francis called for an Easter truce: "Stop the attacks in order to help the exhausted population. Stop," he said.

Ecumenical Patriarch Bartholomew, the spiritual head of Eastern Orthodox Christians worldwide, called for humanitarian corridors in Mariupol and other areas of Ukraine, where he said "an indescribable human tragedy is unfolding".

Ukrainian refugees filled churches across central Europe.

"I pray that this horror in Ukraine ends soon and we can return home," said Nataliya Krasnopolskaia, who fled to Prague from Odesa last month, one of the more than 5 million Ukrainians estimated to have escaped the country.

MORE EQUIPMENT, TALKS

Preparing for the visit by Blinken and Austin, Ukrainian officials had drawn up a list of weapons urgently needed from the United States, including anti-missile systems, anti-aircraft systems, armoured vehicles and tanks, Zelenskiy aide Igor Zhovkva told NBC News on Sunday.

The United States and NATO allies have shown growing readiness to supply heavier equipment and more advanced weapons systems. Britain has promised to send military vehicles and is considering supplying British tanks to Poland to free up Warsaw's Russian-designed T-72s for Ukraine.

The European Union is preparing "smart sanctions" against Russian oil imports, possibly some form of oil embargo, The Times reported https://www.thetimes.co.uk/article/brussels-prepares-to-hit-russia-with-smart-sanctions-on-oil-imports-k3f230l3j on Monday, citing the European Commission's executive vice president, Valdis Dombrovskis.

Turkish President Tayyip Erdogan said after talks by phone with Zelenskiy that Ankara was ready to assist in negotiations with Russia. Zelenskiy said he discussed with Erdogan the need for the immediate evacuation of civilians from the southern city of Mariupol, the site of the biggest battle of the conflict.

Russian forces on Sunday again attempted to storm the Azovstal steel plant, the main remaining Ukrainian stronghold in Mariupol, Ukrainian officials said, adding that more than 1,000 civilians are also sheltering there.

Ukraine on Sunday proposed a "special" round of negotiations with Russia to discuss the fate of the civilians and Ukrainian troops still trapped in the city, though Moscow has yet to respond publicly.

The aim of the talks would be to establish an immediate ceasefire in Mariupol, "multi-day" humanitarian corridors, and the freeing or swapping of Ukrainian fighters trapped in the plant, Ukraine's Arestovych said.

Serhiy Volyna, commander of Ukraine's 36th Marine brigade forces in Mariupol, said Russia was hitting the plant with air and artillery bombardments.

"We are taking casualties, the situation is critical... we have very many wounded men, (some) are dying ... the situation is rapidly worsening," Volyna said.

Moscow has previously declared victory in the city and said it did not need to take the plant.

Capturing Mariupol would link pro-Russian separatists who control parts of the regions of Donetsk and Luhansk that make up the Donbas with the southern Black Sea peninsula of Crimea, which Moscow seized in 2014.

Ukraine estimates tens of thousands of civilians have been killed in Mariupol and says 100,000 civilians are still in the city. The United Nations and Red Cross say the civilian toll is at least in the thousands.