Russian Defense Ministry Chief Spokesman Igor Konashenkov announced the surrender of “1,026 Ukrainian servicemen” in Mariupol a day after President Joe Biden referred to Russia’s invasion of Ukraine as a “genocide” for the first time. The surrender in Mariupol could set Russia up to take full control of the city.

Mariupol has been one of the most infamous Ukrainian cities during the invasion. Attacks on a maternity hospital and a theater in the city helped the United States determine that Russia had committed war crimes during the invasion.

On Tuesday, Ukraine Deputy Defense Minister Hanna Malyar said the government was investigating whether Russia used phosphorus munitions while attacking Mariupol. A day later, Mariupol Mayor Vadym Boychenko accused Russia of trying to carry out a “chemical attack,” saying “it did hit our guys.”

“There are testimonies of several people from surrounding villages near the city, they sensed a sweet taste in their mouth,” Boychenko said Wednesday. “It scared some residents in nearby villages, and young men and women started leaving these villages near the city because it became unsafe.”

The announcement of the Ukrainian surrender in Mariupol came just hours after the term “genocide” came up in a speech President Biden gave Tuesday. He was speaking at an event about steps his administration is taking to address rising fuel costs because of the war.

“Your family budget, your ability to fill up your tank, none of it should hinge on whether a dictator declares war and commits genocide a half a world away,” Biden said. He later clarified the comment, saying “yes, I called it genocide because it has become clearer and clearer that Putin is just trying to wipe out the idea of being able to be Ukrainian.”

Ukrainian President Volodymyr Zelenskyy praised Biden for his comments, sending out a tweet describing them as “true words of a true leader.” According to a White House statement, Biden and President Zelenskyy spoke on the phone Wednesday.

“I just spoke with President Zelenskyy and shared with him that my Administration is authorizing an additional $800 million in weapons, ammunition, and other security assistance to Ukraine,” Biden said in the statement. “As Russia prepares to intensify its attack in the Donbas region, the United States will continue to provide Ukraine with the capabilities to defend itself.”