"If the counting process continues like this, ignoring our call and plea, we will not accept the results," Prachanda said in the press conference, adding that the election process is "against the people's mandate, conspiratorial and an unexpected one".
He also blamed national and international power centres for his and his party's defeat.
Prachanda's remarks came after he had congratulated the Nepali people for participating in the polls Wednesday and making it largely free and fair.