Pro-Russian social media accounts have begun circulating video shot in the Kherson region of Ukraine on Monday showing celebrations of Victory Day.
The events appear to have drawn small crowds waving red flags and carrying flowers.
Ukrainian activists in Kherson have claimed that Russia has brought in people from Crimea to bolster the numbers attending.
Russian state media have been quick to report on Victory Day celebrations in occupied parts of Ukraine.
State-run news agency RIA Novosti reported that in Kherson, a procession in memory of the heroes of the Great Patriotic War was taking place for the first time.
Vladimir Saldo, the head of the city administration, congratulated residents who gathered in the Park of Glory with portraits of their relatives who participated in the war, the news agency said.
People with Russian flags and a large banner with the inscription "Immortal Regiment" are walking from the park through the streets of the city, according to RIA Novosti.
The videos available so far suggest a modest turnout for the rally.
On Monday, Kirill Stremousov, the Russian-appointed deputy chairman of the region's military-civilian administration, told RIA Novosti that the Kherson region would strive for integration with Russia.
"We are not planning to hold a referendum and create a republic," he told the agency.
"Today, based on the opportunities that we have, we will integrate as much as possible into the Russian Federation."