In 1991 the USSR was dissolved, Estonia restored its independence. The administrative boundary became de facto national border of Russia and Estonia that required formal recognition, delimitation and establishing of crossing points. During early 1990-ties there were attempts to foment a pro-Estonian sentiment in the Russian borderland, where billboards invited local delegates to the Citizen's Congress of Estonia and simulated border landmarks placed along 1920 border. For Russians living in Pechory district the Estonian immigration authorities offered Estonian citizenship on much more concessionary terms than to most Russians in Estonia. Russia reciprocated with easier naturalization rules for the resident non-citizens living in Estonia. In 1993 a pro-autonomy plebiscite was conducted in Narva, but Estonian court invalidated its results.