Up to 3,000 people took part in the unionist rally, as estimated by Moldovan police, that was organized by the Actiunea 2012 (translated as Action) movement, which combines the two countries' non-governmental organizations.
George Simion, the movement's leader, was detained on Wednesday and issued a five-year deportation note by the Moldovan authorities for alleged activities against the constitutional order of the state. As a dual citizen, Simion was escorted by authorities to the western border checkpoint of Leuseni and declared persona non-grata in Moldova.
Demonstrators marched through the center of Chisinau carrying Moldovan, Romanian and EU flags along with pro-unity posters with slogans reading "Greater Romania — Old Borders" and "Bessarabia is Romania."
Reinforced police units helped avoid clashes between pro- and anti-unity supporters who stand for Moldovan sovereignty.
Saturday's march was timed to coincide with the 203rd anniversary of the Treaty of Bucharest between the Russian and Ottoman empires. A narrow territory between the Dniester and Prut rivers to the east and west was transferred to Russia under the deal that ended the 1806-1812 Russian-Turkish war.
A number of Romanian and Moldovan politicians consider this strip of land, part of the greater region historically referred to as Bessarabia, as Romanian territory.