U.S. Vice President Joe Biden and a top official of the ruling Liberal Democratic Party agreed Thursday to strengthen bilateral relations and make efforts toward signing a Pacific free trade pact.

Shigeru Ishiba, the No. 2 man in Prime Minister Shinzo Abe's LDP, told reporters he and Biden agreed it is important that the Japan-U.S. alliance remains strong "to deal with various Chinese activities" in the Asia-Pacific region.

The LDP secretary general did not elaborate but was apparently referring to China's maritime activities to press its claims in territorial disputes with other countries in the East China Sea and South China Sea, including Japan.