Konstantin Kosachev, head of the International Affairs Committee of the State Duma, Russia's lower house of parliament, said that three more organizations had each received invitations to send an additional 25 monitors.
The groups are the Parliamentary Assembly of the Council of Europe, the Parliamentary Assembly of the Organization for Security and Cooperation in Europe (OSCE), and the Inter-parliamentary Assembly of the Commonwealth of Independent States.
"We decided to raise the number of invited monitors to 55 from each organization" he said. Each group had previously received invitations to send 30 observers to the elections.
The decision to raise the number of monitors comes following comments by the OSCE's election monitoring arm, the Office for Democratic Institutions and Human Rights (ODIHR), which said on November 16 that its monitors had been "continuously denied entry visas into Russia" and accused Moscow of being unwilling to cooperate with the organization.
A letter sent to the Russian election commission said that organization, whose presence at elections is seen as vital by most Western governments, "regretted" that it "would be unable to deliver its mandate."
The Central Election Commission head, Vladimir Churov, retorted that accreditation documents had been sent to the OSCE on time, and its refusal to monitor the polls for the State Duma, Russia's lower house, was surprising.
"All the relevant documents, including visas, are with the Warsaw-based office ODIHR. I do not see what could have prompted such a decision," the election official said.
The State Duma is currently dominated by the pro-Kremlin United Russia. President Putin announced in October that he would head the party's candidate list at the elections, a move which has all but guaranteed United Russia a resounding victory at December's polls.