Russ­ian forces have tak­en four bor­der vil­lages in Ukraine’s north­east­ern Sumy re­gion, a lo­cal of­fi­cial said Tues­day, days af­ter Russ­ian Pres­i­dent Vladimir Putin said he had or­dered troops to es­tab­lish a buffer zone along the bor­der.

Sumy bor­ders Rus­sia’s Kursk re­gion, where a sur­prise Ukrain­ian in­cur­sion last year cap­tured a pock­et of land in the first oc­cu­pa­tion of Russ­ian ter­ri­to­ry since World War II. The long bor­der is vul­ner­a­ble to Ukrain­ian in­cur­sions, Putin said, and cre­at­ing a buffer zone could help Rus­sia pre­vent fur­ther cross-bor­der at­tacks there.

Mean­while, a Russ­ian bomb­ing cam­paign that had es­ca­lat­ed in re­cent days slowed overnight, with far few­er Russ­ian drones tar­get­ing Ukrain­ian towns and cities.