After examining signatures in favor of ex-premier Kasyanov's candidacy for the March 2 election, the Central Election Commission (CEC) invalidated 13.38% of them, well over the 5% limit beyond which a candidate's registration is denied.
"I would like to point out that 600,000 signatures have been verified out of 2 million, and that only 213 of these raised doubts that they were penned by individuals other than those named in the documents," Kasyanov told journalists in Brussels.
"This is less than one hundredth of a percent of what is needed [for invalidation]. The remainder are technical complaints that we will contest; we are sure that formalities and technical complaints cannot serve as grounds for a registration denial," he said.
Under Russian law, a presidential candidate has to collect at least 2 million signatures in his or her support.
"As far as I know, no decision has been taken. A protocol on the second stage of [inspection of the signatures] was handed to my representatives this morning, and we are considering the complaints," Kasyanov said.
Election authorities wrote down their complaints in a protocol following checks of two selections of the signatures, and a case was launched on Tuesday on falsification charges. Kasyanov's campaign team has dismissed the forgery claims as "political pressure."
Mikhail Kasyanov was prime minister during Putin's first term, but was dismissed in 2004. Commonly known in Russia as "Misha two-percent," a reference to bribery allegations concerning his time in office, Kasyanov is heavily associated with the Yeltsin years, which saw widespread hardship in Russia, and has little popular support. Misha is the diminutive version of the Russian name Mikhail.
The CEC has so far registered four candidates for the March 2 presidential elections: First Deputy Prime Minister Dmitry Medvedev, Communist Party leader Gennady Zyuganov, the Liberal Democratic Party leader Vladimir Zhirinovsky and Andrei Bogdanov, the leader of the tiny Democratic Party.
Medvedev, who has been publicly backed by President Putin, is the clear front-runner.