Stepping up efforts to strengthen his ties with world leaders, Prime Minister Shinzo Abe has agreed with Russian President Vladimir Putin to accelerate work toward concluding a formal postwar peace treaty, a government official said.

During a 20-minute phone conversation Friday, Abe and Putin also decided to begin making arrangements for the prime minister to visit Russia in the new year, according to the official. Abe's predecessor, Yoshihiko Noda, had to cancel a trip to Moscow scheduled for this month following the Lower House's dissolution in November for a snap election Dec. 16.

Abe also spoke over the phone Friday with Australian Prime Minister Julia Gillard, British Prime Minister David Cameron, Indian Prime Minister Manmohan Singh, Indonesian President Susilo Bambang Yudhoyono and Vietnamese Prime Minister Nguyen Tan Dung, officials said.