Zelensky says he has agreed to talks with Russia.

"KYIV, Ukraine — President Volodymyr Zelensky of Ukraine agreed on Sunday to talks with Russia “without preconditions,” even as President Vladimir V. Putin further escalated tensions by placing his nuclear forces on alert.

“We agreed that the Ukrainian delegation would meet with the Russian delegation without preconditions on the Ukrainian-Belarusian border, near the Pripyat River,” Mr. Zelensky announced on his official Telegram channel, describing a phone call Sunday with President Aleksandr G. Lukashenko of Belarus.

Mr. Lukashenko “has taken responsibility for ensuring that all planes, helicopters and missiles stationed on Belarusian territory remain on the ground during the Ukrainian delegation’s travel, talks and return,” Mr. Zelensky continued.

But just before Mr. Zelensky’s announcement, Mr. Putin issued a new threat to the West, which has increasingly rallied behind Ukraine as its citizens and its military fought back against the Russian invasion. In brief remarks aired on state television, he told his defense minister and his top military commander to place Russia’s nuclear forces on alert, characterizing the move as a response to the West’s “aggressive” actions.

Not only are Western countries implementing “illegitimate sanctions” against Russia, Mr. Putin said, “but senior officials of leading NATO countries are allowing themselves to make aggressive statements directed at our country.” Many analysts had expected Mr. Putin to use nuclear threats to push back against the West as tensions rose.

Linda Thomas-Greenfield, the U.S. ambassador to the United Nations, said in an interview with CBS News’s “Face the Nation” that Mr. Putin “is continuing to escalate this war in a manner that’s totally unacceptable.” She added: “We have to continue to condemn these actions.”

Details about the meeting at the border were not yet clear, including who would participate. Mr. Zelensky earlier on Sunday had rejected holding talks in Belarus — as Russia has been demanding — because Russia staged part of its invasion from Belarus after amassing troops in the country. But Mr. Zelensky’s stance shifted after he spoke by phone with Mr. Lukashenko, the Belarusian leader, Mr. Putin’s closest international ally.

The Russian delegation, led by a former Russian culture minister, Vladimir Medinsky, is already in Belarus.

The diplomatic news came on a day when Russian troops, at least for a time, drew closer to the center of Kharkiv, Ukraine’s second largest city, according to videos and photographs analyzed by The New York Times."