Security forces flood Moscow to quell poll fraud protests

Thousands of security forces were patrolling the streets of Moscow today after more clashes with demonstrators angry over alleged election fraud.

At least 250 people were detained in the Russian capital last night, police said, as protesters continued to accuse prime minister Vladimir Putin and his United Russia party of rigging Sunday's parliamentary polls.

At Triumphal Square about 500 people faced a larger group from United Russia and the pro-Kremlin Nashi youth movement. Putin opponents chanted slogans as loyalists beat drums and shouted "Putin, Russia". There were reports fireworks were thrown at the prime minister's supporters.

About 200 people were arrested at a similar rally in St Petersburg, and 25 in the southern city of Rostov-on-Don. It was the second night of big protests.

Opposition leader and former deputy prime minister Boris Nemtsov was arrested in St Petersburg. It is believed he is still being held. Authorities said more than 53,000 security forces have been deployed in Moscow since Sunday's poll, in which United Russia's vote fell from 64 to just under 50 per cent.

It kept a majority in the Duma, but opponents reported vote fraud including ballot-box-stuffing. International observers reported irregularities and EU foreign policy chief Catherine Ashton pointed to a "lack of media impartiality." Mr Putin denied the claims.