Washington ? Independent candidate Ralph Nader, denied a spot on the Arizona ballot, on Friday accused the Democrats and presidential candidate John Kerry of engaging in political “dirty tricks.”

Just hours before the developments in Arizona, Nader complained that the Democratic Party had “stepped up its obstruction tendencies” in challenging his ballot access. The consumer advocate said he had called the Kerry campaign three times Thursday, asking to chat with the candidate.

“We have to get a clarification if they’re going to engage in dirty tricks,” Nader told reporters at a news conference to criticize multinational corporations.

The Kerry campaign dismissed Nader’s complaints, arguing that Democrats were following the rules when they legally challenged Nader’s signatures to get on the ballot.