Russian-installed authorities in the occupied Ukrainian region of Kherson said on Wednesday that they plan to evacuate around 50,000-60,000 people over the next six days amid escalating pressure from a Ukrainian counteroffensive.

Russian-installed governor Vladimir Saldo said authorities were moving civilians to the left (east) bank of the Dnipro River in order to "keep people safe" and allow the military to "act resolutely".

"I drove through the regional centre this morning. On the exterior, there was nothing to suggest there was a lot of pressure," Saldo said.

"But when I arrived at the river port I saw that the boats were waiting and are already loaded with people ready to go to the left bank of the Dnipro," he said, adding that the situation "is getting tense."

He said an estimated 10,000 people a day would be moved over the next six days, and that some regions in Russia were being prepared to accept people.

Kherson residents have received text messages warning of the urgent need to evacuate, Russian state TV reported. More than 5,000 have left in the last two days, Saldo said.

Russia took control of most of Ukraine's southern Kherson region shortly after invading in February, and proclaimed it as annexed in September in a move that Kyiv and the West denounced as illegal.

Russian forces have been driven back by 20-30 km (13-20 miles)

in the last few weeks

, and risk being pinned against the western bank of the Dnipro as Ukraine wages a counteroffensive in the region. (Writing by Caleb Davis; editing by Guy Faulconbridge and Mark Trevelyan)