MARSEILLE, France — China laid down its most explicit postwar marker on Thursday, with Vice Premier Ding Xuexiang using the second day of the Marseille donor conference to unveil a 12-billion-dollar yuan-denominated lending facility for Iranian and Iraqi reconstruction projects, a move that injected Beijing directly into an aid architecture being shaped largely by European, Gulf and Japanese capitals.

Ding, the highest-ranking Chinese official at the two-day gathering at the Palais du Pharo, told delegates that the facility would be administered through the China Development Bank and the Asian Infrastructure Investment Bank, with disbursements tied to specific energy, transport and water projects rather than to the central donor pool managed by the United Nations. He framed the offer as a complement to Wednesday’s broader $84 billion pledge target, but several Western diplomats in the hall read it as a signal that Beijing intended to keep its own track distinct.

“China will not place itself outside this process, but neither will it dissolve into it,” Ding said in remarks delivered in Mandarin and simultaneously translated. “Our cooperation with Iran and Iraq has its own history and its own instruments. We bring those instruments to the table.”

The Chinese offer is modest in scale relative to the conference’s headline target — Saudi Arabia and the United Arab Emirates between them pledged more than 31 billion dollars on Wednesday — but unusual in design. Roughly 70% of the facility, according to a term sheet circulated to a handful of delegations and reviewed by reporters, will be denominated in yuan rather than dollars, with repayment scheduled over 15 years and a grace period of up to four. Borrowers would be permitted to settle interest in oil deliveries valued at a moving reference price, a structure that Chinese energy traders have used informally with Tehran for years but that has rarely been written into a multilateral framework.

“It is a competitive offer dressed as a contribution,” said Dr. Lin Wei-han, a senior fellow at the Institute of Southeast Asian Studies in Singapore. “The terms are friendlier than what the Europeans can put on paper, the conditionality is lighter than what the Gulf will accept, and the currency play does real work for Beijing’s longer project of pulling commodity invoicing away from the dollar.”

French officials, while careful to welcome the announcement publicly, sought during a midday break to coordinate a response with German and Japanese counterparts. A French diplomat involved in the drafting of the conference’s closing communique, speaking on condition of anonymity to describe internal deliberations, said the European hosts were determined that the final document reference a “single coordinated reconstruction architecture” and avoid language that could be read as endorsing parallel tracks.

“We are not going to refuse Chinese money, and frankly we cannot,” the diplomat said. “But we will not let the communique read like an invitation to fragment the effort before it has begun.”

Iran’s delegation, led by Foreign Minister Abbas Araghchi, was visibly receptive. Araghchi held a roughly 40-minute meeting with Ding on the sidelines of the morning plenary, the third such bilateral between the two since the April 15 ceasefire. Iranian state media described the encounter as “warm and detailed” and said both sides had agreed to convene a joint technical committee in Beijing later this month to identify the first tranche of projects. Iraqi Prime Minister Mohammed Shia al-Sudani met Ding shortly afterward and signaled interest in routing financing for the Basra-Faw rail corridor and parts of the southern grid through the new facility.

The choreography underscored a broader pattern that has emerged since the ceasefire: Tehran and Baghdad are working hard to keep multiple suitors at the table, accepting Gulf and European pledges while preserving room for Chinese and, to a lesser extent, Russian participation. Russia, whose deputy foreign minister attended the opening but skipped Thursday’s sessions, has not made a financial pledge.

For Washington, which is represented at Marseille at the deputy secretary level rather than by Secretary of State Marco Rubio, the Chinese announcement complicated an already cautious posture. A senior State Department official, briefing reporters by phone from Washington, said the administration had been “consulted” on the broad outlines of the Chinese offer through diplomatic channels and that it did not on its face violate the conditional sanctions-relief framework agreed in Geneva last month. The official declined to say whether specific projects financed through the facility might trigger secondary-sanctions review.

Among Asian capitals, the response was more openly divided. Japanese officials, who co-chair the conference, pressed Chinese counterparts during a closed-door session to ensure that any yuan-denominated lending was reported through the UN tracking mechanism that Tokyo helped design. South Korea, India and Indonesia, all of which made smaller pledges on Wednesday, have largely avoided public comment but are watching closely; an Indian diplomat said New Delhi’s concern was less ideological than practical, focused on whether Chinese financing of Iraqi and Iranian rail would complicate the India-led Chabahar corridor expansion announced last week.

The Marseille conference is scheduled to close Friday with a joint communique and a pledge ledger that organizers hope will exceed the 84-billion-dollar target by roughly 10%. Conference co-chair Catherine Colonna told reporters Thursday evening that drafting on the final text had grown “more intricate” over the course of the day but remained on track, and that further announcements on coordination mechanisms with the Chinese facility would be made before the gavel falls.