When President Barack Obama phoned Shinzo Abe, the prime minister-in-waiting, on Tuesday, they agreed to arrange a summit in the U.S. as early as January, according to an official who took part in the 10-minute chat.

"I told (Obama) that I'd like to strengthen the Japan-U.S. alliance, as this will help stabilize the Asian region," Abe said afterward.

According to the official, Obama's side approached Abe on Monday afternoon to arrange the teleconference to deliver a congratulatory message on the Liberal Democratic Party's victory in the Lower House election Sunday.

Abe told Obama that China's power has grown and the security environment in the East China Sea and South China Sea has become tougher. He pledged that Japan will "carry out its responsibilities" so the power balance in Asia will not be destabilized, according to the official.

Abe also told Obama that Tokyo will cooperate closely with the U.S. on dealing with North Korea's recent firing of a long-range ballistic missile, the official said.

In response, Obama said the Japan-U.S. relationship is very important for the stability of the region as well as the rest of the world and promised to strengthen bilateral cooperation in both the political and economic areas, the official said.

One of Abe's key campaign promises was to strengthen the Japan-U.S. military alliance and thereby keep China and North Korea in check.

But neither of the two leaders went into further details during the conversation, not mentioning, for example, the Japan-China territorial dispute over the Senkaku Islands in the East China Sea, according to the official.