Russian people took to the streets of Moscow for the second day following the victory of the ruling United Russia Party in Sunday’s parliamentary elections, which are now marred by suspicions of voting irregularities.

Hundreds of demonstrators held a rally near Moscow’s Triumphal Square, chanting slogans against Russian Prime Minister Vladimir Putin and calling for his resignation. Local police blockaded the square and detained hundreds of protesters.

The Russian Foreign Ministry criticized the U.S. for raising concerns over the alleged irregularities in the weekend parliamentary election.

The ministry said that election-related remarks by U.S. State Secretary Hilary Clinton and the White House are unacceptable.