According to Russian state media, President Vladimir Putin paid a surprise visit to Mariupol, a Ukrainian port city captured by Russian forces after pounding much of it to ruins.
An official video shows Mr Putin driving through the streets at night and then going to a concert hall. The location has not been confirmed by the BBC.
Mr Putin’s visit would be his first to a newly occupied Ukrainian territory.
According to the Tass news agency, he arrived by helicopter and met with some locals.
A Russian official can be heard in the video explaining to Mr Putin how the city is being rebuilt.
Mariupol has been under Russian occupation for more than ten months after being devastated in one of the conflict’s longest and bloodiest battles.
The visit comes one year after Moscow launched an airstrike on a Mariupol theater where hundreds of civilians were taking refuge. At least 300 people are believed to have died when the building collapsed.
According to Ukraine and human rights organizations, the attack was a war crime.
According to the UN, this is one of the incidents for which Mr Putin and his regime could face legal consequences.
The International Criminal Court issued an arrest warrant for Mr Putin on Friday for alleged war crimes involving the illegal deportation of Ukrainian children to Russia. It means he could be arrested if he visits any of the court’s 123 member countries.
Mr Putin paid an unannounced visit to Crimea on Saturday to commemorate the ninth anniversary of Russia’s annexation of the territory from Ukraine.
According to Russian state media, he visited a new Russian arts school, a children’s summer camp, and future cultural projects such as the New Russia museum and the Museum of Christianity.
Kiev has vowed to liberate all Russian-occupied territories, including Crimea, which Russia annexed in 2014.
During his visit, Mr Putin is also said to have met with top Russian military commanders in Rostov-on-Don, a Russian city just east of Mariupol.