The authorities in Kazakhstan have launched a criminal investigation after a digital billboard displayed a Ukrainian flag during a visit by Russian President Vladimir Putin on Wednesday.

Kazakh police are investigating the brief appearance of the Ukrainian flag on a large LED screen in the capital city, Astana, during a visit there by Russian President Vladimir Putin, Kazakhstan's interior ministry said on Thursday.

Russian President Vladimir Putin arrived on Wednesday in the Kazakh capital of Astana, where he was greeted by his counterpart President Kassym-Jomart Tokayev.

Russian President Vladimir Putin arrived in Kazakhstan on Wednesday for a two-day trip aimed at shoring up ties with his Central Asian ally as tensions mount over the Ukraine war.

Russian President Vladimir Putin visited Kazakhstan on Wednesday, and discussed boosting energy and industry ties and easing a row over farm goods with the Central Asian nation which exports most of its oil through Russia but is exploring alternatives.

Russian President Vladimir Putin arrived in Kazakhstan on Wednesday for a state visit aimed at securing Russia's role in building the Central Asian nation's first nuclear power plant and strengthening economic ties with its largest neighbor.

By Lidia Kelly and Tamara Vaal ASTANA (Reuters) -Russian President Vladimir Putin will discuss energy ties on a visit to Kazakhstan this week, the Kremlin said on Tuesday, a trip that comes amid trade tensions with the Central Asian nation,