Trump accepted the invitation as he attended the summit of the initiative aimed at strengthening ties among twelve countries placed between the Baltic, the Adriatic and the Black Sea.

Quizzed about when Trump can be expected in Slovenia, Foreign Minister Karl Erjavec told the press after the weekly government session in Ljubljana, that President Pahor would have to "provide first-hand information" when he gets back from Warsaw.

This is not the first time that the idea for Trump, whose wife comes from Slovenia, to visit Slovenia has been put forward.

When he took office, an idea was floated that Slovenia could host the first meeting between Trump and Russian President Vladimir Putin. The same idea was then proposed by a Russian MP.

When he presented the idea to US Vice President Mike Pence at the Munich Security Conference in February, Pahor stressed that Slovenia was an interesting country to host the meeting because it is "unequivocally commitment to the EU and NATO" and at the same time maintained "good relations with Russia".

In Warsaw, the US president addressed the event and met the host, Polish President Andrzej Duda, with whom he discussed US military support to this European country, and the co-host, Croatian President Kolinda Grabar-Kitarović.

The Croatian president told Trump that she valued the US stance in the aftermath of the Slovenian-Croatia border arbitration ruling that the border dispute between Slovenia and Croatia was a bilateral issue.

The White House later issued a press release saying that the US president had told his Croatian counterpart to do everything in her power to speed up the process of reconciliation in the Western Balkans.

Meanwhile, Erjavec also said today that he had written a letter with regards to the arbitration ruling that was to be handed to US Secretary of State Rex Tillerson in Warsaw by Foreign Ministry State Secretary Iztok Mirošič.

The point of the letter is that nobody "expects the US to side with Slovenia or Croatia", Erjavec explained. "We wish [the US] takes the side of international law and the respect of court rulings".

Since Tillerson was not in the US delegation in Warsaw, Mirošič handed over the letter to Trump's advisor on national security.