OSAKA (Reuters) - U.S. President Donald Trump on Friday said he hoped for productive talks with Chinese President Xi Jinping on a trade war that is casting a shadow on global growth, but said he had not made any promises about a reprieve from escalating tariffs.

The trade feud and signs of a global slowdown have loomed over a two-day Group of 20 (G20) summit in the Japanese city of Osaka, where Trump and Xi met in passing and prepared for one-on-one talks on Saturday.

To lay the groundwork, Chinese Vice Premier Liu He met Trump’s treasury secretary, Steven Mnuchin, and Trade Representative Robert Lighthizer at the hotel where the U.S. delegation was staying, a source familiar with the talks said.

Expectations have dimmed that the world’s two biggest economies can ease tension when Trump and Xi meet.

“At a minimum it will be productive. We’ll see what happens and what comes out of it,” Trump told reporters after a series of meetings with leaders where he made clear that his priority was two-way trade deals to boost the U.S. economy.

Asked, however, if he had promised Xi a six-month reprieve on imposing new tariffs on a $300 billion list of Chinese imports, Trump said: “No.”

Trump has already imposed tariffs on $250 billion of Chinese imports and is threatening to extend those to another $300 billion of goods, effectively everything China exports to the United States. China has retaliated with tariffs on U.S. imports.

Asian shares stumbled and gold slipped on Friday, as doubts grew that the highly anticipated meeting between the two leaders would bring progress. Wall Street edged higher.

The best-case scenario for the talks was a resumption of trade negotiations, Marc Short, the chief of staff for U.S. Vice President Mike Pence, told reporters at the White House on Friday.

Talks fell apart in May after the United States accused China of reneging on reform pledges made earlier in negotiations.

In Beijing, foreign ministry spokesman Geng Shuang said he hoped the U.S. side could meet China halfway.

“This accords with the interests of both countries and is what the international community is hoping for,” he told a news briefing.

China has consistently pushed back against criticism from Western countries, especially the United States and the European Union, about things like intellectual property rights and the difficulty of doing business in China.

“China’s promise to expand its opening up is not just a cheque that can’t be cashed,” Xi told German Chancellor Angela Merkel at a side meeting in Osaka.

THREAT TO GLOBAL GROWTH

Trump’s administration also has trade feuds with India, Japan and Germany, whose leaders he met on Friday.

Trump said he saw U.S. trade prospects improving, days after criticizing the U.S.-Japan security treaty and demanding that India withdraw retaliatory tariffs.

“I think we’re going to have some very big things to announce. Very big trade deal,” Trump said before he began talks with Indian Prime Minister Narendra Modi. He gave no details.

A White House official said the two leaders had called on their teams to work on mutually beneficial trade solutions.

Trump also made a push to discuss U.S. concerns about Chinese telecoms equipment maker Huawei [HWT.UL].

The United States has pressed its allies to shun Huawei in their fifth generation, or 5G, networks on security grounds. Trump has also suggested easing U.S. restrictions on Huawei could be a factor in a trade deal with Xi.

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“We actually sell Huawei many of its parts,” Trump said at his meeting with Modi. “So we’re going to be discussing that and also how India fits in. And we’ll be discussing Huawei.”

Several leaders warned that the growing Sino-U.S. trade friction was threatening global growth.

“The trade relations between China and the United States are difficult, they are contributing to the slowdown of the global economy,” European Commission President Jean-Claude Juncker told a news conference.

Xi also warned about the protectionist steps he said some developed countries were taking.

“All this is destroying the global trade order ... This also impacts common interests of our countries, overshadows peace and stability worldwide,” Xi told a gathering of leaders of the BRICS grouping on the sidelines of the G20.

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REFORMING WORLD TRADE RULES

Modi, at the same meeting, called for a focus on reforming the World Trade Organization (WTO) and Russian President Vladimir Putin decried what he called efforts to destroy the Geneva-based body.

“We consider counter-productive any attempts to destroy WTO or to lower its role,” Putin said.

The situation of the global economy was worrying, as trade felt the effect of “protectionism (and) politically motivated restrictions,” he added.

Russian Economy Minister Maxim Oreshkin said there was no agreement on how to reform the WTO system, whose rules Washington believes are outdated, though a Japanese official said G20 members agreed on the importance of reform.

The G20 leaders were also struggling to find common ground on issues such as information security, climate change and migration, said Svetlana Lukash, a Russian official helping to coordinate the meetings.

A White House official took a more positive view, saying there was a “good sense of unity in the room” between most leaders on working together on economic issues.

“China was less positive in its outlook which was in stark contrast to basically everybody else,” said the official, who spoke on condition of anonymity.

Trump, who often castigates trading partners on Twitter and at raucous political rallies, put a positive spin on trade developments.

“I appreciate the fact that you’re sending many automobile companies into Michigan and Ohio and Pennsylvania and North Carolina,” Trump told Japanese Prime Minister Shinzo Abe, who had presented him with a map showing the locations of Japanese auto investments in the United States.

Abe urged G20 leaders to send a strong message in support of free and fair trade, warning that trade and geopolitical tensions were rising and downside risks to the global economy prevailed. He also said he wanted to see momentum towards WTO reform.

Japanese and U.S. officials will meet next month to accelerate progress toward a trade deal, Economy Minister Toshimitsu Motegi told reporters after meeting Lighthizer, but added that they did not discuss a target date.