Democratic Party of Japan leader Naoto Kan, facing growing calls to resign over his failure to pay pension premiums, indicated to a DPJ executive Sunday that he will step down as head of the largest opposition party, party sources said.

"The term of office of the new leader should be the remainder of my term in accordance with party regulations," Kan was quoted as telling the executive, who urged Kan to resign soon, in a phone conversation.

On a television program earlier in the day, Kan said, "I'm fully aware of and taking (growing intraparty calls for resignation) very seriously."