Dutch Prime Minister Mark Rutte (L) and Bulgarian Prime Minister Boyko Borissov attend a press conference in Sofia, Bulgaria, Feb. 6, 2018. Visiting Dutch Prime Minister Mark Rutte here on Tuesday evening expressed the reluctance of his country to support Bulgaria's bid to join the border-free Schengen Area, urging more efforts. (Xinhua/Wang Xinran)

SOFIA, Feb. 6 (Xinhua) -- Visiting Dutch Prime Minister Mark Rutte here on Tuesday evening expressed the reluctance of his country to support Bulgaria's bid to join the border-free Schengen Area, urging more efforts.

The Netherlands welcomed the continuing Bulgarian aspiration to fully join the Schengen acquis, Rutte said at a joint press conference after meeting with Bulgarian Prime Minister Boyko Borissov.

He admired the work done by Bulgaria and Prime Minister's Borissov personal initiative in this effort, Rutte said.

"Really a lot has been done particularly in the last couple of years in implementing necessary policies to make this happen," Rutte said. "But the work is not yet finished."

Schengen accession required commitment and responsibility for all parties involved also in Bulgaria -- government, opposition and of course society at large, Rutte added.

Borissov said in turn that the Netherlands is the largest foreign investor in Bulgaria, with over 7.1 billion euros (some 8.7 billion U.S. dollars) invested in his country.

"That means we have the full trust of the Dutch business," Borissov said.

Borissov said Bulgaria would do its best to send positive signals to the Dutch Parliament, showing that it is a disciplined country respecting financial rules, with economic growth, reliably guarding the Schengen border.

Bulgaria and Romania had hoped to join Schengen, but some Schengen members such as the Netherlands and Finland have blocked their efforts, expressing reluctance due to concerns over corruption and security situation in the two Balkan states.

The Schengen zone, which currently embraces 26 European countries, acknowledges the abolishment of their internal borders with other member nations and outside, for the free and unrestricted movement of people, goods, services and capital.