In June 1854, the Allied expeditionary force landed at Varna, a city on the Black Sea's western coast (now in Bulgaria). They made little advance from their base there.:175–176 In July 1854, the Turks under Omar Pasha crossed the Danube into Wallachia and on 7 July 1854, engaged the Russians in the city of Giurgiu and conquered it. The capture of Giurgiu by the Turks immediately threatened Bucharest in Wallachia with capture by the same Turk army. On 26 July 1854, Tsar Nicholas I ordered the withdrawal of Russian troops from the Principalities. Also, in late July 1854, following up on the Russian retreat, the French staged an expedition against the Russian forces still in Dobruja, but this was a failure.:188–190