Japanese Prime Minister Shinzo Abe has pushed for improved relations with China during a brief meeting in Russia with Chinese President Xi Jinping.

Japanese officials said Friday the five-minute exchange occurred on the sidelines of the G20 summit in Saint Petersburg.

China’s official Xinhua news agency acknowledged the two leaders met Thursday after President. Xi “encountered” Prime Minister. Abe in a VIP room at the G20 summit.

Xinhua said President. Xi expressed concern that China-Japan ties face “grave difficulties” that Beijing is “unwilling to see.”

But on Thursday, a Chinese delegation spokesperson at the summit said the responsibility for improved relations “does not lie with China.”

China was angered after Japan last year purchased a group of disputed islands in the East China Sea from their private Japanese landowner.