Ukrainian casualties reported as Russian forces target Odessa

May 2 (UPI) -- Local officials say a Russian rocket attack on the southern Ukrainian city of Odessa late Monday resulted in civilian casualties, including the death of a 15-year-old boy, official media reported.

Serhiy Bratchuk of the Odessa Regional Military Administration told national television the slain boy was among an unknown number of non-combatants killed and wounded in the attack targeting the city's infrastructure, according to the state-run Ukrinform news agency.

The Odessa City Council reported that at least one other child was wounded in the attack while a religious building was also badly damaged.

Odessa regional governor Maksym Marchenko said the Russians targeted a key bridge spanning the Dniester River's estuary into the Black Sea just west of Odessa, the Australian Broadcasting Corporation reported.

In his daily video address on Monday, Ukrainian President Volodymyr Zelensky said operations to evacuate civilians from a besieged steel plant in the southern port city of Mariupol are still ongoing.

"We continue to do everything to rescue our people from Mariupol," he said. "The evacuation operation continues. Tomorrow we also expect movement through humanitarian corridors from Berdiansk, Tokmak and Vasylivka."

Zelensky issued the assurances following reports that last-gasp efforts to rescue hundreds of civilians still trapped in the holdout Azovstal steel works had run into delays and that the evacuees could be taken to Russia instead.

Meanwhile in the United States, administration officials announced that first lady Jill Biden will travel to Eastern Europe later this week in a show of support for Ukrainian refugees amid Russia's war.

Biden will depart Washington, D.C., on Thursday and arrive at Mihail Kogalniceanu Air Base in Romania on Friday when she'll meet with U.S. service members stationed there, her office said.

She will then head to the capital Bucharest on Saturday for meetings with the Romanian government and humanitarian workers before traveling to Slovakia's capital of Bratislava that evening when she'll meet U.S. embassy staff.

On Mother's Day Sunday, she is scheduled to depart for Kosice and Vysne Nemecke, Slovakia, to meet "Ukrainian mothers and children who have been forced to flee their home country because of [Russian President Vladimir] Putin's war," according to Axios.

She will also meet "humanitarian aid workers and local Slovakians who are supporting families who have sought refuge in Slovakia during this crisis."

Before returning the the United States, she'll meet with Slovakian government officials on May 9.

Since the war began Feb. 24, nearly 5.5 million people have fled Ukraine, with more than 3 million seeking refuge in Poland and more than 800,000 in Romania, according to the U.N. High Commissioner for Refugees. Slovakia has taken in almost 400,000 refugees.