President Kurmanbek Bakiyev won a second term in Thursday's election, taking 83 percent of the vote, according to official results in the Central Asian country that is critical to U.S. strategy in Afghanistan.
But the opposition is crying fraud, and the election has come under sharp international criticism.
"This was not an election, it was shameless deception," Bakyt Beshimov, campaign manager for the main opposition candidate, said Saturday. "We are ready to organize meetings and protests against this outrage and disgrace."
The United People's Movement said in a statement that protest rallies "against the thieves of our votes" will begin Wednesday.
Protests sparked by allegations of fraud in a national election in 2005 led to chaos after demonstrators stormed into the presidential building and forced longtime leader Askar Akayev to flee; he eventually resettled in Russia.
Stability in Kyrgyzstan, a nation of 5 million on the western border of China, is of strong interest to both Russia and the United States. The country hosts a U.S. air base crucial to operations in Afghanistan and is the focus of competition between Washington and Moscow for regional influence.
Beshimov spoke at a news conference where recordings were played that appeared to show men casting multiple ballots and a single group of voters being bused to numerous voting stations.
Central Elections Commission chairman Damir Lisovsky said copies of the footage submitted to the authorities have been sent to prosecutors and will be fully investigated.
"In those polling stations where those types of incidents did indeed take place, we have not recognized the results of the vote," he said.
Opposition claims of election fraud were lent weight Friday by the Organization for Security and Cooperation in Europe's election-monitoring arm, which said the vote was marred by ballot-box stuffing and widespread irregularities in vote counting. The European Union supported the report.
"We fully agree with the OSCE's finding that election day was a disappointment," Beshimov said.
The report said observers rated over half the vote counts at precincts as not acceptable.
Lisovsky said the elections commission will examine issues raised by the organization's report, but complained that it appeared to contradict the findings of other international monitoring groups. Observers from the Commonwealth of Independent States, a group of former Soviet republics, praised the election as "open and free."
The main opposition candidate, Almazbek Atambayev, has dismissed the election as fraudulent and is demanding a rerun.
Beshimov said Saturday that exit polls carried out by opposition supporters showed that Atambayev won around 60 percent of the vote.
The government has maintained silence on the outcome of the vote and charges of electoral fraud, and Bakiyev has not appeared in public since the vote.
Bakiyev's supporters say he has increased government spending and boosted salaries and pensions, as well building many new schools and hospitals. But the global financial crisis has slammed Russia and neighboring Kazakhstan, devastating Kyrgyzstan's economy because it relies heavily on remittances and trade.
Under a recent deal to extend the lease of the U.S. air base at Manas, Kyrgyzstan will receive $60 million in annual rent, more than triple the previous amount, plus a further $120 million in investment and aid.
Bakiyev has also secured more than $2 billion in aid and loans from Russia.
By Associated Press Writer Peter Leonard