MINSK (Reuters) - Belarusian security forces detained dozens of protesters on Saturday as crowds rallied in central Minsk accusing President Alexander Lukashenko of rigging last month’s election. One group of women chanted “Our president is Sveta” - referring to opposition politician Sviatlana Tsikhanouskaya who they say won the vote. Riot police dragged many of them into vans and arrested other protesters nearby. Belarus, a former Soviet republic closely allied with Russia, has been rocked by street protests since authorities said Lukashenko won by a landslide. He has denied rigging the Aug. 9 election and dismisses opposition accusations of mass arrests and rights abuses as a Western smear campaign. On Saturday, video on social media showed a masked officer ripping a red and white flag out of the hands of Nina Baginskaya, a 73-year-old activist who has become a central figure in the protests since scuffling with police last month. In the footage, police drag her to a van. Local media said she was later released. Protesters have used the red and white flag that Belarus adopted after the 1991 breakup of the Soviet Union, before Lukashenko restored the Soviet version four years later. Six journalists were detained at the rally on Saturday but promptly released, according to the Belarusian Association of Journalists. Tsikhanouskaya issued a statement on social media condemning the security forces’ actions. “We all deserve that our dignity and civil rights be respected,” she said. “We know this and that is why we cannot be stopped.” Lukashenko, a 66-year-old former collective farm manager, was sworn in for a sixth term on Wednesday in a ceremony held without warning, prompting thousands to take the streets of the capital.