This was reported by the daily Dnevnik on Thursday and confirmed by Pahor's office, which said the letter had arrived 11 days ago.

It has not yet been determined when Pahor is to go to Moscow, but Dnevnik reported that he is to be accompanied by a business delegation. The president had already announced a visit to Russia before Putin's arrival.

Although Putin's visit had primarily been commemorative in nature, dedicated to Russian war casualties in Slovenia, the pair also touched on other topics, ranging from security issues to economic cooperation.

Putin also brought a ministerial delegation and while no concrete deals were agreed, Slovenian entrepreneurs had positive reactions to the visit.