Prime Minister Shinzo Abe is exploring the possibility of visiting Russia in April or May to discuss a territorial dispute dating back to the end of World War II with Russian President Vladimir Putin, government sources said Sunday.

Abe is sending former Prime Minister Yoshiro Mori to Russia in February as his special envoy. After that trip, Abe hopes to finalize arrangements for his first official trip to Russia since becoming prime minster again late last month, the sources said.

Mori, who has close ties with Putin, will bring a letter from Abe when he travels to Russia on a trip aimed at setting the stage for a summit between the leaders, government officials said.