Romanians have begun voting in a presidential runoff between the prime minister who promises stability and a city mayor who says he will fight corruption.

Prime Minister Victor Ponta is favored over the mayor of the city of Sibiu, Klaus Iohannis. Ponta led by 10 percentage points in the Nov. 2 first round.

Corruption probes of senior Ponta aides appear not to have dented the 42-year-old former prosecutor's chances. Iohannis, 55, promises an independent justice system.

Thousands protested in Romania after expats in Paris, London, Munich and elsewhere said they had to stand in line for hours and were unable to vote in the first round. The government says it has improved the voting procedure.

The winner will replace President Traian Basescu, who steps down after 10 years.