MOSCOW (Reuters) - Russian forces are preparing to try to take a village called Lyptsi located about 30 km (19 miles) north of Kharkiv, Ukraine's second largest city, according to a Russian-installed official quoted by Russia's RIA state news agency.

Russia last week opened a new front in the Ukraine war by pushing swiftly over the border into the Kharkiv region of northeastern Ukraine with small groups of highly mobile units, a move that has forced Ukraine to rush in troops from other areas.

President Volodymyr Zelenskiy postponed all his foreign trips as Ukraine's battlefield situation continued to deteriorate on Wednesday and Kyiv said fighting was raging in the northeastern border town of Vovchansk in Kharkiv region.

"The most important city, which is now on the verge of complete liberation, is undoubtedly Volchansk," said Vitaly Ganchev, a Russian-installed official in Ukraine, told Russian state television, RIA reported.

He said Russian troops were already on the approaches to the village of Lyptsi, on one of the main road routes to Kharkiv.

"Next is the settlement of Lyptsi - our guys are already on the outskirts. Work is beginning to liberate it, aviation and artillery are working constantly, they do not stop," Ganchev said.

The Ukrainian military said on Thursday that its defensive moves had forced Russian troops to reduce the tempo of the offensive in the north of the Kharkiv region.

(Reporting by Reuters; Writing by Guy Faulconbridge; Editing by Andrew Osborn)