The Russian occupation authorities in Ukraine's southern city of Kherson have postponed a so-called referendum on joining Russia, on security grounds, BBC reported.
"This is being paused because of the security situation," said Kirill Stremousov, deputy head of the Russian-appointed administration there.
He said heavy Ukrainian shelling had made a key Kherson bridge impassable.
Ukraine and its Western allies have denounced the referendum plans in Kherson and other areas as illegal.
Meanwhile, Ukraine says its forces have recaptured Vysokopillya, a small town some 167km (104 miles) north of central Kherson.
That gain - not verified independently - is part of a counter-offensive in the south launched by the Ukrainian army last week.
His photo caption says: "Vysokopillya, Kherson Region. Ukraine. Today."
President Zelensky said Ukrainian forces had recaptured two "population centres" in the south, but did not name them.
Russia has been planning referendums in Kherson and the southern Zaporizhzhia region, most of which it controls.
He said barges transporting civilians across the Dnieper (Dnipro) river were also coming under Ukrainian fire, as was the city's infrastructure, according to BBC.
Ukraine has deployed US-made Himars multiple rocket launchers in its drive to push the Russians out of the city - the first to fall to them after their 24 February invasion.
As well as Kherson, Russia has announced plans for referendums in other captured territory, similar to that held in Crimea after its troops seized the peninsula in 2014.
Ukraine's Deputy Prime Minister Iryna Vereshchuk urged civilians to leave Kherson as fighting intensifies in the area. She has also warned that any who participate in the planned Russian referendum are liable to face Ukrainian prosecution.
Russia's invasion has destabilised life in Ukraine to such an extent that it is not clear who could vote in such referendums anyway. The Crimea vote in 2014, held under military occupation, was not recognised internationally, BBC reported.
