KYIV, Ukraine — The American secretaries of state and defense met Sunday night with Ukraine’s president, Volodymyr Zelensky, in the highest-level visit to the country’s capital by an American delegation since the start of Russia’s invasion.

The meeting with State Secretary  Blinken and Defense Secretary Austin, which was confirmed by a senior Ukrainian official, came as Ukraine pressed the West for more powerful weapons against Russia’s campaign in the Donbas region of eastern Ukraine, where Moscow’s forces sought to dislodge the last Ukrainian troops in the battered port of Mariupol.

“Yes, they’re meeting with the president. Let’s hope something will be decided on further help,” Ukrainian presidential adviser Oleksiy Arestovych told Russian lawyer and activist Mark Feygin on his YouTube show “Feygin Live.” The United States has not yet commented.

Before the session with Messrs. Blinken and Austin, Mr. Zelensky said he was looking for the Americans to produce results, both in arms and security guarantees.

“You can’t come to us empty-handed today, and we are expecting not just presents or some kind of cakes, we are expecting specific things and specific weapons,” he said.

Mr. Zelensky’s last face-to-face meeting with a top American official was February 19 in Munich with Vice President Harris, five days before Russia’s invasion. While the West has funneled military equipment to Ukraine, Mr. Zelensky has stressed repeatedly that his country needs more heavy weapons, including long-range air defense systems and warplanes.

Mr. Zelensky’s meeting with American officials took place as Ukrainians and Russians observed Orthodox Easter. Speaking from Kyiv’s ancient St. Sophia Cathedral, Mr. Zelensky, who is Jewish, highlighted its significance to a nation wracked by nearly two months of war.

“The great holiday today gives us great hope and unwavering faith that light will overcome darkness, good will overcome evil, life will overcome death, and therefore Ukraine will surely win!” he said.

Still, the war cast a shadow over celebrations. In the northern village of Ivanivka, where Russian tanks still littered the roads, Olena Koptyl said “the Easter holiday doesn’t bring any joy. I’m crying a lot. We cannot forget how we lived.”

The Russian military reported hitting 423 Ukrainian targets overnight, including fortified positions and troop concentrations, while its warplanes destroyed 26 Ukrainian military sites, including an explosives factory and several artillery depots.

Since failing to capture Kyiv, the Russians have aimed to gain full control over the eastern industrial heartland, where Moscow-backed separatists controlled some territory before the war.

Russian forces launched fresh airstrikes on a Mariupol steel plant where an estimated 1,000 civilians are sheltering along with about 2,000 Ukrainian fighters. The Azovstal steel mill where the defenders are holed up is the last corner of resistance in the city, otherwise occupied by the Russians.

Mr. Zelensky said he stressed the need to evacuate civilians from Mariupol, including from the steel plant, in a Sunday call with President Recep Tayyip Erdogan of Turkey. Mr. Erdogan was scheduled to speak later with Russian leader Vladimir Putin.

Mariupol has endured fierce fighting since the start of the war because of its location on the Sea of Azov. Its capture would deprive Ukraine of a vital port, free up Russian troops to fight elsewhere, and allow Moscow to establish a land corridor to the Crimean Peninsula, which it seized from Ukraine in 2014.

More than 100,000 people — down from a prewar population of about 430,000 — are believed to remain in Mariupol with scant food, water or heat. Ukrainian authorities estimate over 20,000 civilians have been killed. Recent satellite images showed what appeared to be mass graves to the west and east of Mariupol.