Almost 30 world leaders are attending a two-day summit promoting China's One Belt, One Road initiative that Beijing hopes will revive ancient trade routes from Asia to Europe and Africa -- and breathe new life into its own economy.
At the opening of the meeting on Sunday, Chinese President Xi Jinping pledged to pump an extra $124 billion into the China-bankrolled project, which involves a huge network of ports, railways, roads and industrial parks.
A number of leaders including Russian President Vladimir Putin and Turkish counterpart Recep Tayyip Erdogan applauded the initiative, which Xi unveiled in 2013 and hailed as "a project of the century".
"In these times, when the temptation is great to respond to the crisis of globalisation by increasing isolation, and by raising walls, this initiative highlights a vision of connectivity, cooperation and dialogue across Europe and Asia but also other parts of the world," Greek Prime Minister Alexis Tsipras said.
British finance minister Philip Hammond said London was "ready to work with all Belt and Road partner countries to make a success of this initiative".
But some officials expressed caution.
German Economy Minister Brigitte Zypries called for transparency to ensure that the calls for investment bids are "non-discriminatory".
Some Belt and Road projects are already raising concerns in certain countries.
India has voiced displeasure at the China-Pakistan Economic Corridor, a Belt and Road project aimed at linking northwestern China to the Arabian Sea.
Signup to our newsletter and follow us on Facebook and Twitter!
Others at the summit warned sustainable lending practices were needed to ensure countries hosting the hundreds of projects were not saddled with unsustainable debts.
"Unprofitable investments are not good for anybody," said Andras Vertes, chairman of GKI Economic Research.
The initiative, which is Xi's signature foreign policy, spans some 65 countries representing 60 percent of the world population and around a third of global gross domestic product.
The China Development Bank has earmarked $890 billion for some 900 projects.
While the summit has been given almost non-stop coverage on Chinese state-run television, attention at the event was distracted by North Korea's latest missile test on Sunday.
Xi did not mention the North during his speech, but it was discussed at his bilateral meeting with Putin.
"Both parties expressed their concern over the escalation of tensions" on the Korean peninsula, Kremlin spokesman Dmitry Peskov told reporters.
The Chinese foreign ministry also issued a statement saying it opposed such missile tests and called for restraint from all parties.
The delegates from both Koreas held a brief meeting at the summit on Sunday, according to South Korea's Yonhap news agency.
The summit will resume on Monday at Yanqi Lake in a Beijing suburb near the Great Wall.