Ukraine’s president has not altered his position that the international borders in place when the Soviet Union collapsed in 1991 must continue to be recognised, a presidential adviser said on Thursday. Russia annexed the Crimea peninsula from Ukraine in 2014 but the region is still regarded by the United Nations as part of Ukraine. Russia has also recognised declarations of independence by two self-proclaimed republics in eastern Ukraine which rose up against Kyiv’s rule in 2014. Those two areas and Crimea were part of Ukraine when it declared independence from the Soviet Union in 1991.Ukraini…