Prime Minister Shinzo Abe said Monday that Japan is ready to cooperate with China’s “One Belt, One Road” cross-continental infrastructure development scheme, under certain conditions.

Speaking at a forum in Tokyo on Asia’s future, Abe said those conditions would include “harmony with a free and fair Trans-Pacific economic zone,” alluding to the terms of the Trans-Pacific Partnership free trade pact, to which Japan is a signatory but China is not.

The One Belt, One Road initiative, put forward by Chinese President Xi Jinping in 2013, would involve massive investment to connect up both a land-based economic belt based off the ancient Silk Road and a maritime corridor spanning from China to Southeast Asia, India, Africa and Europe.

Xi has said he wants to create a “big family of harmonious coexistence” through the project, but skeptics see it as a bid to position China as a viable alternative to U.S. global leadership.

Abe lauded the initiative’s “potential to connect East and West as well as the diverse regions found in between.”

But he cautioned that it is “critical for infrastructure to be open to use by all, and to be developed through procurement that is transparent and fair.”

“I furthermore consider it essential for projects to be economically viable and to be financed by debt that can be repaid, and not to harm the soundness of the debtor nation’s finances,” Abe said, adding Tokyo is “ready to extend cooperation from that perspective.”

The statement may be part of efforts to foster warmer relations with China as Japan seeks to host a postponed trilateral summit with the leaders of China and South Korea by the end of the year.

It also comes amid speculation that the United States could be considering joining the China-led Asian Infrastructure Investment Bank, a move that would likely put pressure on Japan to follow suit.

Japan and the United States, the main backers of the decades-older Asian Development Bank, are the only members of the Group of Seven developed nations that have not signed up with the AIIB.

Abe said last month he could be open to considering joining the AIIB if questions surrounding projects’ environmental impacts and other issues are resolved.

Toshihiro Nikai, the secretary-general of Abe’s Liberal Democratic Party and known for his pro-China stance, attended a One Belt, One Road-themed international forum in Beijing last month and is said to support the AIIB idea.