UPDATE 1-Belarus police detain dozens as crowds chant against Lukashenko

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By Andrei Makhovsky

MINSK, Sept 26 (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 - before riot police dragged many of them into vans. Other protesters were arrested nearby.

Belarus, a former Soviet republic closely allied with Russia, has been rocked by mass street protests since Lukashenko's claim of a landslide victory in an Aug. 9 vote.

He has denied rigging the election and dismissed opposition accusations of mass arrests and abuses as a Western smear campaign.

On Saturday, video on social media showed police detaining Nina Baginskaya, a 73-year-old who has become a central figure of the protest movement after scuffling with police last month.

The footage showed a masked riot police officer ripping a red and white flag out of Baginskaya's hands before dragging her into a van.

Protesters have used the flag that Belarus adopted after the 1991 breakup of the Soviet Union, before Lukashenko restored the Soviet version four years later.

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. (Writing by Gabrielle Tétrault-Farber; editing by Jason Neely and Andrew Heavens)