The death toll from Saturday's missile attack on an apartment building in Dnipro has risen to 45, including six children, according to Borys Filatov, the city's mayor.

The search and rescue operations have ended, according to the emergency services.

In addition to the fatalities, there were 79 people wounded, including 16 children, according to emergency services.

Thirty-nine people were rescued from the rubble, including six children, emergency services said.

-ABC News' William Gretsky

Ukrainian soldiers arrived in the United States on Sunday to begin training on the Patriot air defense missile system at Fort Sill, Oklahoma, a U.S. military official said.

The training at Fort Sill is expected to last several months, and then switch briefly to Europe, officials said.

The U.S. military’s expanded combat training of Ukrainian forces in Germany began Sunday, Gen. Mark Milley, chairman of the Joint Chiefs of Staff, told The Associated Press.

-ABC News' Luis Martinez

Emergency crews have rescued 39 people, including six children, who were buried under the rubble caused by a missile strike on a high-rise apartment complex in Dnipro over the weekend, Ukrainian President Volodymyr Zelenskyy said in his Monday evening address.

The death toll remains at 40, including three children, he said.

The Kremlin denied being responsible for the attack, saying Russia doesn’t strike residential areas and claiming the destruction was a result of Ukrainian air defense.

"The debris of the house destroyed by the Russian missile is still being dismantled in Dnipro," Zelenskyy said. "I thank everyone who is carrying out this rescue operation. Every employee of the State Emergency Service and police, every doctor, every volunteer. Everyone who is involved."

-ABC News' Ellie Kaufman

Emergency workers were still looking for survivors Monday following a strike on a high-rise apartment building on Saturday in the Ukrainian city of Dnipro.

The death toll rose to 40 dead, including three children, making it the deadliest strike on a residential area in Ukraine in the last three months.

Ukrainian President Volodymyr Zelenskyy called the attack "Russian terror," saying Ukraine was "fighting for every person, every life" under in rubble in Dnipro and would "find everyone involved in this terror."

The attack on an apartment building destroyed 72 units and wounded 75 residents.

Rescuers have been using cranes to remove chunk after chunk of rubble, looking for survivors.

One of the survivors, Yevgeni, told ABC News that he was in his bed when the missile struck his apartment.

"I can’t understand. I didn’t hear any bang, any voice, any sound of the missile," said Yevgeni, adding that he suffered a head injury and that his broken window frame fell on him.

He described seeing smoke and "a lot of dust" at the scene. He said "the most scary thing (was hearing) the voices of people screaming."

Local resident Natali Nodykova told ABC News that a friend called her to tell her there was a bombing in her neighborhood.

"My son was alone at home and of course I was afraid," Nodykova said.

Emergency workers rescued 39 people, Ukrainian officials said. Twelve people remained unaccounted for Monday.

The attack was caused by a Soviet-made Kh-22, a long-range missile used to take down aircraft carriers, according to the Ukrainian Air Force.

The massive 13,000-pound missile causes huge amounts of casualties when used in civilian areas.

The Kremlin denied the attack, saying Russia doesn’t strike residential areas and claiming the destruction was a result of Ukrainian air defense.

The same type of weapon had been used in a previous attack on a shopping mall in the town of Kremenchuk back in July that killed 22 people, according to Ukrainian authorities.

-ABC News' Ibtissem Guenfoud, Bruno Roeber, Oleksii Pshemyskiy, Matt Gutman and Max Uzol

U.S. President Joe Biden made an unannounced visit to war-torn Ukraine on Monday, arriving in Kyiv as Washington signals its ongoing support ahead of the one-year anniversary of Russia's invasion.

Biden's visit came ahead of a planned meeting with NATO allies in Poland. He is expected to give a speech at the Royal Castle Arcades in Warsaw on Tuesday evening to offer an appraisal of international support during the first year of the war and to address "how we will continue to stand with the people of Ukraine for as long as it takes," White House spokesperson Karine Jean-Pierre said in a statement earlier this month.

Biden also plans to meet in Poland with leaders of the Bucharest Nine, a group of eastern NATO allies formed in 2015 in response to Russia's annexation of Ukraine's Crimean Peninsula.

Ukrainian President Volodymyr Zelenskyy made a dramatic visit to the United States in December, his first known international trip since the Russian invasion began in February 2022. Zelenskyy met with Biden at the White House in Washington, D.C., before addressing members of U.S. Congress on Capitol Hill.