Democratic Party of Japan lawmakers intensified efforts Friday to whip up support for the two contenders in the ruling party's presidential election, Prime Minister Naoto Kan and longtime kingpin Ichiro Ozawa.

The battle between the two camps escalated a day after Ozawa's announcement that he would run in the Sept. 14 poll, which will determine whether Kan can continue to serve as prime minister after only three months in office.

Kan shrugged off widespread concerns the party could be split by Ozawa's challenge. "I'm sure that all party members will be able to work together after the election," he said.